On my left rib cage right below my breast I have what seem to be a rib sticking out it has gotten a lot bigger since I first noticed it. It causes a lot of pressure along with a great deal of pain to my chest all the way around to my shoulder blade. I showed his to a doctor the had me do a mamagram which did not show anything the pressure and pain is getting unbearable.What could be causing this and what do I do to correct it.