Subacromial bursitis has similar symptoms to Supraspinatus tendinitis with shoulder pain over a 60 degree arc when the arm is lifted sideways.
Symptoms of subacromial bursitis can be similar to those of supraspinatus inflammation or injury in the shoulder. There will be pain and weakness in the arm, particularly when it is lifted sideways through a 60 degree arc. Pain may also be felt when you press in at the inside front of the upper arm. If it is the tendon that is injured rather than the bursa there is likely to be more pain when the arm is lifted up sideways against resistance.