Quoting *Super*Mom*:" As I was bending over to put my pants on this morning, I felt my back stretch. It hurt to come back up, ... [snip!] ... was wondering if this is happening to anyone else? I'm 19 wks and I'm not big at all, do you think it's even pregnancy related?"
It's your muscles stretching. Getting a back brace at a baby store and work on doing yoga and other muscle strengthing activities. Your back is hurting because your muscles are too weak. It could also have to do with how the baby lays...so work on repositioning your chunka! I had two 9 pound babies. It's not fun. lol