The shoulder, one of the largest, most complex joints in the human body, is formed where the upper arm bone fits into the shoulder blade like a ball and socket. Because the shoulder joint is so complex, it’s subject to injury and conditions that can cause chronic pain. Most people probably don’t give their shoulders much though — until they experience shoulder pain or discomfort.
Conditions That Can Cause Shoulder Pain
Chronic shoulder pain can result from the following conditions caused by illness, overuse, and injury. Because the shoulder joint is made up of three bones (the collarbone, shoulder blade, and upper arm bone), the shoulder joints are the most flexible joints in the body. Because the ball portion of the joint (the upper arm) is larger than the socket that holds it, the joint can become injured if the supporting muscles, tendons, or ligaments are damaged. Common reasons why you may experience shoulder pain include:
- Rotator cuff injury – a tear to muscle or tendon surrounding the top of the humerus. If you suffer this injury, you can expect to feel a vague pain in the shoulder that radiates down your arm, a catching sensation when you move your arm, and difficulty sleeping on the affected side.
- Impingement – the scapula presses on the rotator cuff, causing pain when the arm is lifted. If you feel a sharp pain while reaching into your back pocket and pain raising your arm to the side or front of your body, those are good indications you have a shoulder impingement.
- Shoulder dislocation – a bone in the shoulder bone shifts out of position. You should suspect a shoulder dislocation if your shoulder or upper arm pain is so severe you have trouble moving your arm. You may also notice an unusual bump in front or back of your shoulder where the dislocated bone is visible under the skin
- Shoulder tendonitis – an inflamed tendon in the shoulder. Shoulder tendonitis is often accompanied by pain in the outer portion of your upper arm and the front and top of your shoulder. The pain is worse when you raise your hands above your head.
- Bursitis of the shoulder – an inflamed bursa, which is a fluid-filled sac covering the shoulder tendons. Symptoms of shoulder bursitis include pain the worsens over time and worsens when you move your shoulder.
- Shoulder labral tears – the labrum consists of cartilage that covers part of the humerus. A labral tear occurs when this cartilage is torn due to sudden injury or the gradual aging process.
- Frozen shoulder – shoulder inflammation that limits movement. This condition usually involves pain that develops gradually, gets worse, then finally goes away within 1 to 3 years.
- Shoulder arthritis
- Osteoarthritis – age-related arthritis that develops after a lifetime of wear and tear on the shoulder joint. This routine wear and tear gradually causes shoulder cartilage to become frayed and rough and the protective space between joints to become smaller. Eventually, the space becomes so compressed that bones and joints rub together, which causes pain.
- Rheumatoid arthritis – inflammation and pain caused when the immune system attacks the shoulder joint.
- Posttraumatic arthritis – occurs when cartilage degenerates and causes pain after a sudden injury (not wear and tear.)
- Rotator cuff tear arthropathy – a common source of shoulder pain that develops over time after a rotator cuff injury.
- Avascular necrosis – bone tissue dies due to loss of blood supply (due to a broken bone or dislocated joint.) The loss of bone tissue causes tiny, painful breaks in the shoulder bone.