Shoulder joint pain is usually specific and often debilitating, but the cause of shoulder injury may be hard to pinpoint. Sudden trauma or gradual overuse can be to blame. The type, degree and duration of pain will offer clues as to whether a muscle, tendon, ligament, joint or bone is causing the pain.
Tendonitis
Repetitive motions that involve overhead reaching or lifting, whether during weightlifting, tennis, swimming or everyday tasks, can cause shoulder injury to muscles and attached tendons. According to the University of Maryland Medical Center (UMMC), damage may be acute, resulting in sudden inflammation of the rotator cuff tendons, or cumulative, causing already-damaged tissue to tear.
Bursitis
Shoulder bursitis can also be caused from the same motions that aggravate tendons and muscles. The Mayo Clinic relates that the bursae, or cushioning tissue between the parts of the shoulder, become inflamed. Bursitis arises when this interstitial tissue is impinged beneath bone during movement. Shoulder pain will be noticeable just under the joint capsule.
Fractures
Fractures can be caused by bone degeneration but are more commonly due to traumatic blows or falls. According to the American Academy of Orthopaedic Surgeons (AAOS), of the shoulder problems involving the shoulder blade, collarbone and humerus, fractures are more likely to occur in the less-protected collarbone and humerus.
Dislocation
Dislocation is a shoulder problem that causes soft tissue injury when the ball of the joint pops out of the socket that holds it in place. The action behind dislocation, reports the AAOS, is a strong outward twist of the joint when the arm is in motion above shoulder level. This can happen during a fall or external impact. Underlying causes of instability in the joint, such as bone or muscle degeneration, may increase the risk of dislocation.
Frozen Shoulder
A frozen shoulder may be caused by traumatic shoulder injuries, but most often, there is no known cause. The shoulder joint capsule is like a hinge that contains ligaments that join the three bones. When these ligaments become inflamed, they restrict movement of the joint and cause shoulder pain. The UMMC notes that frozen shoulder syndrome is often associated with cervical disk degeneration, diabetes, open heart surgery, shoulder surgery or hyperthyroidism.
Arthritis
Shoulder pain that comes and goes but gets worse over time may be due to a form of arthritis. The AAOS lists three conditions that may be prompted by different causes. Osteoarthritis is the degeneration of cartilage over years of wear and tear, usually associated with aging. Rheumatoid arthritis is caused by an autoimmune disease that inflames joint linings. Post-traumatic arthritis may occur after shoulder injury or surgery.
