Rotator Cuff Tear - this usually is related to trauma or activities but sometimes is not. Testing the muscles is a sure way to find out.
General Shoulder Pain Often times patients complain of "shoulder pain" but they really mean pain near the shoulder blade or general shoulder pain that may be related to neck and upper back dysfunction.
Manipulation of the neck and upper back can usually help to alleviate pain and restore normal joint function. A few simple test can determine the cause, it may be simple.