Showing the ball to centerfield=shoulder pain?

I think that showing the ball to center may hurt the back of my shoulder?? could this cause shoulder problems as well as elbow problem?

I don’t think so.

I believe that problems in the back of your shoulder are more likely related to a problem with how you decelerate your arm. Your muscles may simply be weak or you may be cutting short the distance over which your arm decelerates (ala Andy Pettitte).