The shoulder consists of much more than just one joint;  in fact, it is several joints that combine with tendons and muscles to allow a wide range of motion to the arm. Shoulder problems involve the soft tissue-muscles, ligaments, and tendons rather than just bone. Most of these problems can fall into a few categories:

Tendonitis or Bursitis

A muscle is broken down into muscle fibers and tendons. A tendon is a cord that connects muscle to bone. Most tendonitis is the result of an overuse or repetitive motion that can cause inflammation or wearing. Tendonitis can also be present because of mis-alignments in the shoulder and mid thoracic vertebrae.

The tendons that make up the shoulder are called the rotator cuff. The rotator cuff is the arrangement of muscles and tendons that provide shoulder motion and stability.

Sometimes excessive use of one's shoulder can lead to inflammation and irritation in the bursa which is a lubricating sac around the humeral head or shoulder joint. This condition of irritation of the bursa is known as bursitis. Inflammation of the bursa can cause joint stiffening and sometimes cause "frozen shoulder" which is restricted motion of the shoulder.

Injury / Instability

Sometimes injury or instability can cause the bones to shift out of normal position causing a restriction in motion and moderate to severe pain. When instability is present the shoulder may feel like it is slipping out of position or grinding sounds may be heard.

Arthritis

Shoulder pain can also result from calcium deposits or bone spurs. Arthritis in the shoulder involves wear and tear changes caused by inflammation and calcium deposits. Arthritis can be related to work injuries and sports injuries. Most people will find themselves limiting their motion in the shoulder to lessen the pain. Seek treatment for a shoulder injury.

Many patients ignore shoulder pain because they think it will go away. What tends to happen is the longer one waits the more complicating the condition becomes because of the several joints and muscles that are involved with the shoulder. A thorough exam is the best way to find the right treatment to avoid further injury and future discomfort.