I have abdominal pain which started suddenly in between my ribs. I thought it was muscle strain, though I hadn t done any exercises for abs. It started about three days ago, mostly to the left of my lower ribs, then centered, and now seems to have migrated lower-right. Other muscles are still somewhat sore, but pain in lower right is constant, throbbing, feels like it has a heartbeat , and extremely tender when pressed. I can t bend over / tie shoes/ w/out mid muscle feeling like it s going to cramp up.