Prenatal yoga does wonders for back pain as well!!!
I used a maternity body pillow 4 $35 from toys r us and I love it! It's shaped like a candy cane so it elevates my head(which helps with my acid reflux) and gives me something to put between my legs.
U can just buy it on eBay its cheaper on eBay. I haven't gotten one yet but I'm going to cause I have hell sleeping.