When I try to do any type of stomach exercise I get what I call a cramp/pain. It only happens on my right side and the only way I can explain it is that it feels like a rib is going either over or under the other one which in turn causes me to not be able to do the exercises. If I put pressure on that area it don't do it though but I can tell it's trying to. Has this happened to anyone or can you tell me what it could be caused from PLEASE???