I had that problem on and off. A few weeks in the second trimester and then towards the end and beginning of third trimester I go to sleep and will wake I up at 3 am and can't go back to sleep until 6am, which is close to my wake up time to get ready for work. I am currently able to sleep most of the night...we shall see the next 2 months left!
I use a snoogle for back pain. I had it with my dd too and it's helping me loads. I don't know if that is your problem but maybe a diff pillow?
It should get better. Try eating a bit earlier at night. That helped me during that phase.