Back pain help!

Stephanie • Wife to the most amazing man and soon to be mommy Dec 2015 😍💗💙💍
Hey everyone I am 15 +4 and for the last few nights have woken up a ton with back pain throughout the night. When I wake up I turn over to try and relieve it but it's only a short while before I wake up again. I sleep on my side with a pillow between my legs and we have a big comfortable mattress that's only a year old. The only comfortable way to lay is on my back and I know that's not an option anymore. Any advice? Thanks!!!