Im not sure if this is rotator cuff or not. I notice when I practice serve too much this pain starts to come up. I can raise my arm above my head no problem with my palms facing forward, but not when my palms face down. The pain it mostly on the back/top side, almsot feels like its inside the joint. I cant do push ups, but pull ups are fine. Serves are where I notice it the most, but I can still do them, and I only notice it on backhands at full extension/high follow through. does that sound like something a weeks rest will cure?