20 May 2024
Discover the common causes of shoulder pain and learn how to find relief. From muscle strains and joint inflammation to traumatic injuries, this article explores the possible culprits behind your shoulder discomfort. Improve your shoulder health and daily activities by understanding the anatomy and identifying the non-traumatic and traumatic causes of shoulder pain.

If you’ve ever woken up with a throbbing shoulder, you’re not alone. Shoulder pain is a common complaint that can significantly disrupt your daily activities. Whether it was a sudden injury or gradual discomfort, understanding the common causes of shoulder pain can help you find relief and take the necessary steps towards improving your shoulder health. From overuse and muscle strains to joint inflammation and rotator cuff injuries, this article will shed light on the possible culprits behind your hurt shoulder while sleeping.

Common Causes of Shoulder Pain

Anatomy of the Shoulder

The shoulder is a complex joint that allows a wide range of motion and flexibility. It is made up of several bones, muscles, tendons, and ligaments that work together to provide stability and support. Understanding the anatomy of the shoulder is essential in identifying and treating shoulder pain and injuries.

Bones of the shoulder

The shoulder consists of three main bones: the humerus (upper arm bone), scapula (shoulder blade), and clavicle (collarbone). These bones form the shoulder joint, with the humerus fitting into a socket on the scapula called the glenoid. The clavicle connects the shoulder to the rest of the body and provides support and stability.

Muscles of the shoulder

The shoulder is surrounded by a group of muscles known as the rotator cuff, which includes the supraspinatus, infraspinatus, teres minor, and subscapularis muscles. These muscles work together to stabilize the shoulder joint and allow for various movements, such as lifting and rotating the arm. Other muscles in the shoulder, such as the deltoid and trapezius, contribute to overall shoulder strength and mobility.

Tendons and ligaments of the shoulder

Tendons are tough, fibrous tissues that connect muscles to bones, while ligaments connect bones to each other. In the shoulder, the tendons of the rotator cuff anchor the muscles to the bones, providing stability and control during shoulder movements. Additionally, several ligaments within the shoulder joint, such as the acromioclavicular (AC) ligament and the glenohumeral ligaments, help to support the shoulder and prevent excessive movement or dislocation.

Non-Traumatic Causes of Shoulder Pain

Shoulder pain can arise from various non-traumatic causes, including overuse, inflammation, and degenerative conditions. Understanding these common causes can help identify and manage shoulder pain effectively.


Bursitis refers to the inflammation of the bursae, small fluid-filled sacs located around joints that act as cushions between bones, muscles, and tendons. When the bursae in the shoulder become inflamed, it can result in pain, tenderness, and limited range of motion. Bursitis can be caused by repetitive movements, injury, or underlying conditions such as arthritis.


Tendonitis is the inflammation of tendons, often caused by repetitive motions or overuse of the shoulder. Common types of tendonitis in the shoulder include rotator cuff tendonitis and biceps tendonitis. Symptoms may include pain, swelling, and difficulty with daily activities that involve shoulder movements.

Frozen shoulder

Frozen shoulder, also known as adhesive capsulitis, is a condition characterized by stiffness and pain in the shoulder joint. It occurs when the connective tissues surrounding the shoulder joint thicken and tighten, limiting its range of motion. Frozen shoulder usually develops gradually and can be associated with underlying conditions such as diabetes or previous shoulder injuries.

Rotator cuff impingement

Rotator cuff impingement occurs when the tendons of the rotator cuff become trapped or pinched between the bones of the shoulder joint, particularly the acromion (part of the scapula) and the humerus. This can lead to pain and restricted movement, especially when lifting or reaching overhead.

Shoulder arthritis

Shoulder arthritis refers to the degeneration or inflammation of the shoulder joint, commonly caused by wear and tear or autoimmune conditions such as rheumatoid arthritis. Arthritis can lead to pain, stiffness, and reduced range of motion in the shoulder. Different types of arthritis, including osteoarthritis and rheumatoid arthritis, can affect the shoulder joint.

Common Causes of Shoulder Pain

Traumatic Causes of Shoulder Pain

Shoulder pain resulting from trauma or injury can be sudden and debilitating. Understanding the different traumatic causes of shoulder pain can help in recognizing and seeking appropriate medical attention.

Shoulder dislocation

A shoulder dislocation occurs when the humerus is forced out of its socket in the glenoid, leading to severe pain and immobility. This injury often happens during sports activities or due to a fall onto an outstretched hand. Prompt medical intervention is crucial in treating a shoulder dislocation and preventing further damage.

Shoulder fracture

A shoulder fracture refers to a break or crack in one or more of the bones of the shoulder, such as the collarbone, scapula, or humerus. Fractures can occur due to accidents, falls, or direct trauma to the shoulder. Symptoms may include intense pain, swelling, bruising, and difficulty moving the arm.

Acromioclavicular (AC) joint injury

The AC joint is located at the top of the shoulder, where the clavicle meets the acromion. An injury to the AC joint, such as a sprain or separation, can result from a fall onto the shoulder or a direct blow to the area. AC joint injuries can cause pain, swelling, and tenderness, especially when moving the shoulder or lifting objects.

Labral tear

The labrum is a ring of cartilage that surrounds the glenoid, providing stability to the shoulder joint. A labral tear can occur due to acute trauma, repetitive stress, or dislocation of the shoulder. Symptoms may include a popping sensation, pain, weakness, and a feeling of instability in the shoulder.

Clavicle fracture

A clavicle fracture, or broken collarbone, is a common injury that can cause significant shoulder pain and limited movement. This type of fracture often occurs from a fall onto the shoulder or a direct blow to the area. Symptoms may include swelling, deformity, tenderness, and difficulty raising the arm.

Muscle Strains and Tears

Muscle strains and tears can occur in various muscles surrounding the shoulder, leading to pain and functional limitations. Understanding the different types of muscle strains and tears in the shoulder can aid in proper diagnosis and treatment.

Strains in the rotator cuff muscles

The rotator cuff muscles are susceptible to strains, which can result from repetitive overuse or sudden excessive force. Strains in the rotator cuff muscles can cause pain, weakness, and difficulty performing daily activities that involve shoulder movement.

Biceps tendon tear

The biceps tendon connects the biceps muscle to the bone in the shoulder. A tear in the biceps tendon can occur from repetitive overhead activities or sudden forceful movements. Symptoms may include a sudden, sharp pain in the front of the shoulder, weakness, and a bulge in the upper arm.

Trapezius muscle strain

The trapezius muscle is a large muscle that spans from the neck to the middle of the back and shoulder. Straining the trapezius muscle can cause pain, tightness, and difficulty moving the head and shoulders. Poor posture, repetitive activities, and stress are common causes of trapezius muscle strains.

Deltoid muscle tear

The deltoid muscle is the large muscle responsible for the rounded shape of the shoulder. A tear in the deltoid muscle can result from forceful trauma or repetitive stress. Symptoms may include localized pain, swelling, weakness, and limited range of motion in the shoulder.

Common Causes of Shoulder Pain

Nerve-related Shoulder Issues

Shoulder pain can also stem from nerve-related issues, where the normal functioning of the nerves that supply the shoulder is compromised. Identifying these nerve-related shoulder issues can help in determining appropriate treatment options.

Brachial plexus injury

The brachial plexus is a network of nerves that originate from the spinal cord in the neck and control the movement and sensation in the shoulder, arm, and hand. An injury to the brachial plexus, such as during a traumatic event or excessive stretching, can lead to shoulder pain, weakness, numbness, and tingling.

Thoracic outlet syndrome

Thoracic outlet syndrome occurs when there is compression or irritation of the nerves or blood vessels passing through the narrow space between the collarbone and first rib. This can result in shoulder pain, numbness, weakness, and aching, often extending into the arm and hand. Certain postures, repetitive overhead activities, or anatomical abnormalities can contribute to thoracic outlet syndrome.

Suprascapular neuropathy

Suprascapular neuropathy is a condition characterized by compression or damage to the suprascapular nerve, which innervates the muscles of the shoulder joint. This can lead to shoulder pain, weakness, and difficulty with overhead movements. Repetitive overhead activities, direct trauma, or anatomical variations can contribute to suprascapular neuropathy.

Referred Pain from Other Areas

Shoulder pain can sometimes be a result of referred pain, meaning that the pain originates from a different area but is felt in the shoulder. Recognizing potential sources of referred pain is important in understanding the underlying cause of shoulder pain.

Neck problems

Problems in the neck, such as herniated discs, arthritis, or muscle strain, can cause pain that radiates to the shoulder. Nerve impingement in the cervical spine can also result in shoulder pain, numbness, and tingling. Proper evaluation and diagnosis of neck-related issues are crucial in addressing shoulder pain.

Gallbladder disease

Gallbladder disease can lead to referred pain in the right shoulder and upper back. The pain is typically fueled by gallstones blocking the bile ducts, causing discomfort that can radiate to the shoulder. Other symptoms may include abdominal pain, nausea, and bloating.

Heart conditions

Certain heart conditions, such as angina or a heart attack, can cause referred pain in the left shoulder and arm. This is known as referred cardiac pain and is generally accompanied by other symptoms such as chest pain, shortness of breath, and sweating. If you experience these symptoms, seek immediate medical attention.

Overuse and Repetitive Strain Injuries

Overuse and repetitive strain injuries can lead to chronic shoulder pain and dysfunction. Identifying these conditions and making appropriate lifestyle modifications can help prevent and manage shoulder pain effectively.

Shoulder tendinitis

Shoulder tendinitis is the inflammation of the tendons in the shoulder, often caused by repetitive overhead activities or improper mechanics. Symptoms may include pain, swelling, and stiffness, which worsen with activity and improve with rest. Proper warm-up, stretching, and modifying activity levels can help prevent and manage shoulder tendinitis.

Shoulder bursitis

Shoulder bursitis occurs when the bursae in the shoulder become inflamed, often due to overuse, trauma, or underlying conditions such as arthritis. Symptoms may include pain, swelling, and tenderness around the shoulder joint. Rest, ice, and physical therapy are common treatment approaches for shoulder bursitis.

Glenoid labrum tears

The glenoid labrum is a cartilage ring that lines the glenoid socket, providing stability to the shoulder joint. Tears in the glenoid labrum can occur from repetitive stress or traumatic events. Symptoms may include pain, clicking or locking sensation, and a feeling of instability in the shoulder joint.

Inflammation of the rotator cuff tendons

Inflammation of the rotator cuff tendons, known as rotator cuff tendonitis, can arise from repetitive overhead activities, poor posture, or improper shoulder mechanics. Symptoms may include pain, weakness, and difficulty lifting or reaching. Strengthening exercises, physical therapy, and modifying activity levels can be effective in managing rotator cuff tendonitis.

Postural and Alignment Issues

Poor posture and alignment can contribute to shoulder pain and dysfunction. Addressing postural and alignment issues is essential in maintaining a healthy and pain-free shoulder.

Forward head posture

Forward head posture, often associated with rounded shoulders, occurs when the head is positioned in front of the shoulders rather than aligned with the spine. This can lead to muscle imbalances and strain on the muscles and ligaments in the neck and shoulder. Awareness and correction of forward head posture through exercises and stretching can help alleviate shoulder pain.


Kyphosis refers to an increased curvature of the upper back, leading to a rounded or hunched appearance. This postural abnormality can result in imbalances and strain on the muscles and joints of the shoulder. Strengthening exercises, postural correction techniques, and ergonomic modifications can aid in managing kyphosis-related shoulder pain.


Scoliosis is a condition characterized by an abnormal lateral curvature of the spine. Depending on the severity and location of the curvature, scoliosis can contribute to shoulder pain, muscle imbalances, and reduced range of motion. Treatment options for scoliosis-related shoulder pain may include physical therapy, bracing, or in severe cases, surgical intervention.

Shoulder Infections

While relatively rare, shoulder infections can occur, leading to significant pain and swelling. Identifying the signs and symptoms of shoulder infections is crucial in seeking prompt medical attention.

Septic arthritis

Septic arthritis, also known as infectious arthritis, refers to the infection of the shoulder joint, often caused by bacteria or other microorganisms. Symptoms may include severe pain, swelling, redness, warmth, and limited range of motion in the shoulder. Prompt diagnosis and treatment with antibiotics are essential in managing septic arthritis.

Bacterial or viral infections

Bacterial or viral infections, such as cellulitis or shingles, can also affect the shoulder area and cause pain. These infections often involve skin and soft tissue and may result in redness, swelling, tenderness, and the presence of rashes or blisters. Proper diagnosis, treatment, and infection control measures are important in managing shoulder pain associated with infections.

Systemic Conditions Affecting the Shoulder

Systemic conditions, such as autoimmune or inflammatory diseases, can impact the shoulder joint and cause pain and discomfort. Recognizing these systemic conditions can help in developing appropriate treatment plans.

Rheumatoid arthritis

Rheumatoid arthritis is an autoimmune disease that primarily affects the joints, including the shoulder joint. It can lead to joint inflammation, pain, stiffness, and reduced range of motion. Early diagnosis, medical management, and physical therapy can help in managing rheumatoid arthritis-related shoulder pain.


Lupus is an autoimmune disease that can cause inflammation throughout the body, including the shoulder joints. Symptoms may include joint pain, swelling, fatigue, and a butterfly-shaped rash on the face. A multidisciplinary approach involving medical management, physical therapy, and lifestyle modifications is often necessary in addressing shoulder pain related to lupus.

Polymyalgia rheumatica

Polymyalgia rheumatica is an inflammatory condition characterized by pain and stiffness in multiple muscles, including the shoulders. This condition primarily affects older adults and can cause significant discomfort and functional limitations. Prompt medical intervention with anti-inflammatory medications and physical therapy can assist in managing polymyalgia rheumatica-related shoulder pain.

In summary, the shoulder is an intricate joint consisting of bones, muscles, tendons, and ligaments, all working together to facilitate movement and stability. Shoulder pain can have various causes, including non-traumatic conditions such as bursitis, tendonitis, and frozen shoulder, as well as traumatic injuries like dislocation and fractures. Muscle strains and tears can also contribute to shoulder pain, along with nerve-related issues, referred pain, overuse injuries, postural problems, infections, and systemic conditions. Understanding the different causes of shoulder pain and seeking appropriate medical attention can help in managing and preventing further discomfort and dysfunction. Remember, it is always advisable to consult with a healthcare professional for an accurate diagnosis and personalized treatment plan for shoulder pain or injuries.

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