Rotator cuff tendinopathy/tendinosis is degeneration and/or disorganization of rotator cuff tendon tissues (often on account of overuse and repetitive exercise). A corticosteroid injection (“cortisone shot”). This could present temporary pain reduction but doesn't “cure” tendinopathy. There's some issue cortisone may possibly weaken muscle mass and tendon tissue, and this is probably https://www.theorthopaedicandpainpractice.com/what-are-some-shoulder-pain-treatments/