It also could be because your baby sleeps or lays on one or
is positioned to some of your nerves in that area. At this
late in the game, it might be a good idea to call your doctor
and let him/her what is going on. Good luck!
It could be your appendix, and it could be a new muscle pulling. But I wouldn't sit on it, I'd call your doctor's office and get the person on call to contact you, and explain it in detail. At 36 weeks, it could also be contractions (not just BH) that mean it, so call them. Good luck!!!