What is tendonitis, bursitis, impingement?

All of these are part of the same process. When you raise your arm above shoulder level, the top of the shoulder and rotator cuff tendons are pinched beneath the shoulder cap or acromion. The cushion in between is the bursa. The bursa can become inflamed which causes pain with overhead motion, pain at night, and deconditioning of the rotator cuff muscles.