I had the same thing happen to me w/babies #2 & #3. I remember that pain well. You might want to try to get some physical therapy. Alas, it is "just one of those things" w/pregnancy. I tried really hard to keep my weight gain to a minimum (while remaining healthy) just to avoid any added stress to my frame. I also had horrible rib pain. The docs told me part of the trouble was because I'm petite (5'2") & because I have lax joints so the pregnancy hormones made them even more lax, including my pelvis. Have the doctors ever told you that you have lax joints? As a side note, w/2 boys, if you do have lax joints, they might as well. You'll need to be careful about them yanking on each others' arms & dislocating them (nursemaid's elbow). We found out the hard way that my son had inherited my lax joints when his sister dislocated his elbow when he was a toddler. Good luck & hand in there. I found that sitting for long periods of time made the pain worse, so I stood around an awful lot.