I'm expecting baby number 2 and I'm in the same boat. The miracle of life is just plain out ugly and uncomfortable. Keeping busy and active, light exercise and such should help a little. Ask your doctor if Tylenol is ok for you to take.
If the body pillow isn't helping at night you could try something called a snoogle pillow. I've never used one but I hear they are amazing but a little pricey.
Do you sleep with a pillow between your legs? I can't sleep without one. Also, if could be your mattress that's making you uncomfortable. I have a new mattress and it's so hard to get comfortable on but it's such a soft bed! Maybe too soft.
For the back pain I get my fiance to massage my lower back. Try a massager. Also apply heat the the aching area, helps a ton