It's your bra those things put a lot of pressure on everything I had to switch to sports bras .I'm a very bust girl though.
Probably just your growing uterus. Its getting closer and closer to ur ribs. Mine hurt all the time around that week. It'll go away soon but it never hurts to call and ask ur Dr if ur really worried about it
If nothing makes it go away or lessen the pain...you should contact your doc or l&d as abdominal pain that doesn't subside is a sign or preeclampsia
I get it too. It's probably the way the babies positioned. But if it worries you that much, tell your doctor.