I get bad pain in my lower back and in my stomach and found out a lot of mine is gas build up during the day. I found if I lay back in a recliner or in the bath tub I get a lot of relief and the gas can escape. I know tmi lol. I don't know why it builds up but it sure hurts!
I think your utuers is growing accomadate your growing baby. Probably just round ligaments pains have some rest. & lay on ur left side.. Mommy of 2(: