Location of Pain:
- Outside of Shoulder: Pain over the outside of the shoulder often extends down the arm. The pain is often a deep muscle ache. The most common cause of pain over the outside of the shoulder is a rotator cuff problem, including tendonitis, bursitis, or a rotator cuff tear.
- Front of Shoulder: Pain in the front of the shoulder is most commonly related to the biceps tendon. The biceps tendon attaches deep inside the shoulder; problems of the biceps include biceps tendonitis, SLAP tears and biceps tears.
- Top of Shoulder: The most common cause of pain in the top of the shoulder is an abnormal AC joint. Problems of the AC joint include AC arthritis, distal clavicle osteolysis, and shoulder separations.
Timing of Pain:
- Constant pain: Most shoulder problems tend to be bothersome with activity. Rotator cuff tendonitis and tears are usually painful with activities such as reaching or throwing. Constant pain is less typical for these conditions. Frozen shoulder can cause constant pain, but it's usually most painful when reaching behind your back or head.
- Night pain: Pain at night is typical of rotator cuff problems. The reasoning is unclear, but it's not usual for patients with rotator cuff tendonitis, or a rotator cuff tear, to be awakened from sleep or have difficulty falling asleep because of shoulder pain.
Limited active range of motion is typical of a rotator cuff problem. In these conditions, the muscle will not do the appropriate work, so the shoulder feels stiff. But if someone does the work for you by lifting your arm, the shoulder moves normally.
Loss of passive range of motion is typical of a frozen shoulder and arthritis. With frozen shoulder, scar-like tissue builds up around the shoulder, leading to loss of motion—even if someone tries to move it for you. Shoulder arthritis can cause bone spurs and rough cartilage that can also limit mobility.
Your doctor can isolate each of the rotator cuff muscles with specific tests and maneuvers to determine where a problem may exist. Sometimes the rotator cuff muscles don't work normally because of inflammation, and other times because they are detached (torn).
Other people have loose ligaments that result in a chronically unstable shoulder called multidirectional instability. These are usually young, athletic women who feel their shoulder not staying tightly in position (subluxation of the shoulder).
Popping, Clicking, Snapping:
Examining the Shoulder:
Tonino PM, et al. "Complex Shoulder Disorders: Evaluation and Treatment" J Am Acad Orthop Surg March 2009 ; 17:125-136.