During intercourse, I found this to be only when I'm on top though, that I get a sharp pain behind my belly button that gets worse as we continue to have sex. Or if its not the pain behind my belly button it feels like (this sounds funny, but I don't know how else to explain it) it feels like his Penis is shifting my parts inside of me and also causes pain. I've looked up tons of things that it could be and nothing seems to match. Do you have any idea what could be wrong?