This could very well be your gall bladder. That's one of the areas that i had tremendous pain when my gall bladder needed to be removed. Also i hurt between my shoulders and alot of discomfort in my stomach. All my test came back negative for gall bladder problems but ended up being my gall bladder when the Dr. went in to do exploratory surgery. If you have been tested for gall bladder and it was negative keep on persisting for the Dr. to do something.