What Causes Shoulder Pain

What Causes Shoulder Pain?


What causes shoulder pain? The shoulder is comprised of several joints that work in concert with various tendons and muscles to allow for a wide range of motion in the arms. These complex structures, which allow us to perform everyday tasks, from combing our hair to grabbing something from the kitchen cupboard, are also susceptible to injury.

Shoulder pain has a wide range of causes and presents in different ways. It might feel like a sudden, sharp pain triggered by certain movements—or more of a dull ache that lingers for long periods. It can be local to the shoulder joint or radiate through the neck, head, and down through your arms.

Continue reading to learn more about shoulder discomfort and find out how physical therapy has improved the lives of individuals living with shoulder pain, stiffness, and mobility problems.

What Common Conditions Cause Shoulder Pain?

The top causes of shoulder pain fall into a few categories: traumatic, repetitive, anatomical differences, and disuse injuries. Direct trauma to the shoulder, as in a fall or being struck by an object, can damage the structures of the shoulder.

Shoulder injuries also happen through overuse or repetitive motions that are common with certain sports, job tasks, or hobbies. The formation of the bones, muscles, and connective tissues at birth can also impact function, mobility, and pain in the shoulder. Disuse commonly seen with aging also plays a role in shoulder pain, as the risk of several common conditions increases as we get older.


Shoulder instability, including dislocations, happens when the top of the upper arm bone (humerus) is forced out of the cup-shaped socket (glenoid) that is part of the shoulder blade. Dislocation generally causes intense pain along with visible deformation and an inability to move the shoulder. A subluxation is a partial dislocation of the humerus. In a complete dislocation, the top of the humerus comes fully out of the socket.

A single injury can cause instability, or it can happen over time through overuse. Loose or torn ligaments, tendons, and muscles can lead to repeated dislocations or subluxations.

Rotator Cuff Irritations and Injuries

The rotator cuff is a group of tendons and muscles that cover and stabilize the shoulder joint, securing the head of the humerus bone in its socket. A small, lubricating sac (bursa) sits between the rotator cuff and the bone on top of the shoulder (acromion.)

This bursa reduces friction between the tendons and bones of the rotator cuff to allow the arm to move smoothly. Any of these structures can experience inflammation or damage through injury or overuse.

Rotator cuff issues that cause shoulder pain include:

  • Impingement: compression of the bursa or tendons in the shoulder apparent when the arm is raised to shoulder height
  • Bursitis: inflammation of the bursae due to infection, trauma, or chronic irritation
  • Tendinitis: tendon inflammation often caused by degenerative disease or repetitive overhead activities
  • Tears: full or partial tear of the shoulder tendon often accompanied by weakness

Often, the cause of pain is multi-factorial and can be termed Subacromial Pain Syndrome (SAPS) as all of these structures sit between the humerus and the top of the shoulder called the acromion.

People with rotator cuff injuries may have trouble lifting their arm above the head. Left untreated, rotator cuff injuries can result in long-term shoulder weakness and loss of motion. Some patients require rotator cuff surgery and post-surgery physical therapy to restore shoulder mobility and function.

Pinched Nerves

For some, the source of shoulder pain is found in the neck. Cervical radiculopathy is a condition where a nerve in the neck is irritated or compressed at the point where it branches away from the spinal cord.

Along with shoulder and/or arm and hand pain, a pinched cervical nerve can lead to muscle weakness and numbness. This condition can occur in all ages and can be an acute or more degenerative onset of symptoms.

Frozen Shoulder

Frozen shoulder is generalized stiffness that develops when the once flexible tissue encapsulating the shoulder thickens and becomes inflamed. Although the cause of frozen shoulder is not understood at this time, several risk factors for the condition have been identified:

Frozen shoulder typically gets worse over time, usually over a period of several months. Frozen shoulder pain and stiffness can make basic tasks difficult and eventually make it impossible to move the shoulder at all.

The good news is that this condition will ‘thaw’ over the course of a couple of years allowing movement again. Physical therapy can help to regain motion and also to prevent loss of motion from occurring.


Millions of people are diagnosed with arthritis every year in this country. Arthritis is a general term that refers to more than 100 different conditions that cause joint pain and joint disease. Arthritis symptoms include: pain, stiffness, swelling, and reduce mobility in the affected joints.

Osteoarthritis is a joint condition that usually occurs in people aged 50 and older as the smooth cartilage that covers bones wears away. Without that protective space between the bones, they are forced to rub up against each and can cause pain if the joint becomes inflamed. Osteoarthritis commonly affects the shoulder, hip, and knee joints.

Rheumatoid arthritis (RA) is another form of arthritis that affects shoulder joints and other joints throughout the body. It is a chronic inflammatory disease impacting 1.5 million adults in this country. While there are currently no cures for rheumatoid arthritis, medicines, exercise, and lifestyle changes can slow the progression of the disease and significantly improve one’s quality of life.


Fracture is another word for break. Shoulder fractures typically involve breaks of the collarbone (clavicle), the shoulder blade (scapula), and the humerus. Broken shoulder bones usually happen as a result of high-impact trauma to the body like falls, motor vehicle accidents, and contact sports injuries. In additional to severe shoulder pain, shoulder fractures often cause bruising and swelling.

Postural Issues

Some shoulder pain is not caused by an injury at all; it is actually the result of poor posture. Yes, the way you sit, stand, and sleep all affect how you move and feel every day. Our dependence on our mobile phones and other tech devices is also linked to pain throughout the upper body, arms, and hands.

If you carry stress and tension in your upper back and neck, you may experience shoulder pain as well. Postural modifications are a simple and effective ways to correct the issues causing musculoskeletal pain. Physical therapy can address and resolve gait and posture problems for pain-free movement and improved mobility and function in the shoulders and across the body.

What Causes Left Shoulder Pain?

Unless the condition is directly related to a specific injury to one shoulder, joint diseases like arthritis generally affect both sides of the body.

In other cases, pain limited to one shoulder is caused by repetitive motions on that side of the body. For example, a “lefty” pitcher who throws a baseball hundreds of times per week is more prone to developing left shoulder pain and inflammation. In fact, people who are left-hand-dominant are more likely to have pain in the left shoulder because they use that arm and shoulder more frequently.

Left shoulder pain should never be ignored because it can also be indicative of serious conditions including heart attack, stroke, and pancreatitis. Seek immediate medical attention if your pain is accompanied by dizziness, shortness of breath, chest pain or tightness, slurred speech, numbness, and nausea/vomiting.

What Causes Right Shoulder Pain?

Right-shoulder pain can potentially be caused by all of the conditions described above, especially in individuals who are right-arm dominant or use their right arm frequently for sports and other tasks.

As with left-shoulder pain, certain serious health conditions cause symptoms in both shoulders, including a heart attack. Pain in the right shoulder can also be a sign of gallbladder inflammation. Gallbladder inflammation symptoms may span across the entire upper-right quadrant of the body, and is often accompanied by fever, nausea, vomiting, and general malaise.

What Causes Pain Between Shoulder Blades?

The shoulder blades are the ‘wings’ on your back. They are two flat, triangular bones located at the back of the shoulders. They float on top of the rib cage and connect the collarbone with the upper arm bones (scapula.) The shoulder blades provide movement to the shoulders and stabilize the arms.

Shoulder blade pain is often minor and caused by contracting the muscles when stressed, poor posture, or an overstretching, overuse, or tearing of the shoulder blade muscles and/or connective tissues.

Disease or injury to any of the structures of the upper body can cause pain in the upper back between the shoulder blades. That includes osteoarthritis and other forms of arthritis. As the joints become damaged, the supporting muscles and connective tissues are stretched, weakened, or damaged leading to pain in the affected area.

A proper diagnosis is the key to successfully treating shoulder pain for lasting relief. Discuss your symptoms with your healthcare provider and physical therapist, and always seek urgent medical help for severe and sudden unexplained shoulder pain.

Physical Therapy for Shoulder Pain

Your physical therapist is a movement expert. They understand the underlying structural conditions that lead to physical pain and dysfunction. Whether you have recently suffered an injury, are recovering from surgery, or just want to improve the way you move throughout day, physical therapy is shown to reduce pain and accompanying symptoms.

With evidence-based treatments and targeted exercise and stretching, you can finally be free from shoulder pain with physical therapy. Find a physical therapy clinic near you.

Share this article

Schedule an Appointment

You might also like

Range of Motion Exercises

Range of Motion Exercises

Range of motion is how far you can move and extend a joint or muscle independently or with assistance. Injury or disease can affect range...

Physical Therapy treatment for muscle weakness

Physical Therapy Treatment for Muscle Weakness

Do you notice your muscles feeling weaker than usual, even when you exert maximum effort? Is it challenging to do the tasks you used to...

Preventative Physical Therapy

Benefits of Preventative Physical Therapy

Musculoskeletal disorders are among the most debilitating and costly to treat. An estimated half of Americans over 18 will develop a long-term injury of the...