Hi - ever since my daughter was born (she s 11 now), sometimes I get a pain in my left rib as if my muscle underneath is tightening up and pushing through the rib cage. When this happens, you can actually see the muscle pushing out of my rib and it s hard to the touch. What can that be? Is that some kind of hernia? I am female, 49 yrs old, weigh 143 lbs, and I m 5 10 . FYI., I had another baby at 45 (three years ago) and it seems to be worse. Thank you