There are 4 muscles in your rotator cuff – supraspinatus, subscapularis, infraspinatus, and teres minor. These muscles sit on your shoulder blade and insert into the shoulder. Their main job is to stabilize the shoulder joint during movement and contribute to rotation.Tendinopathy is an inflammation and irritation of the tendon leading to pain. Cause of tendonitis involves repetitive activity, overloading, or due to inflammation from other nearby injuries. When left untreated, chronic tendinopathy may weaken the tendon structure and lead to eventual rupture or tear. Your therapist can assess your rotator cuff and create a treatment plan to restore the function of your shoulder.