Pain in Shoulder

I get a sharp pain where my medial deltoids attach to my shoulder when hanging on stall bars for more than 10-15 sec. It gets worse when my back is lifted off of the bars, for example at the top of MnPE6. The only other pain I can compare it too is when I've gotten my shoulder worn out from serving tennis balls too much, but I haven't been playing too much lately. Padding the bars doesnt make too much of a difference

Umm a video would help a lot, but have you thought of how you rotate your elbow in or out?