S.K.
I had the same problem when I was pregnant with my twins and oh, do I feel your pain! During the day it felt like my hip was bruised and at night it was unbearable. We have a sleep # bed with a pillowtop mattress. My husband bought a thick foam pad for our bed. It isn't the egg crate kind. It's like the foam beds that you can buy but it is just a pad about 2 inches thick. I can't remember what it is called. A thicker pillow between your legs might help, too.
Stephanie