Definitely praying. I know how aweful that back pain can be.
The pillow under the leg trick, I swear by! I have serious back problems and if I lay flat on my back, the pain is much worse. I actually use 2 or 3 pillows (depending on how flat they are) and put them under my legs while I am laying on my back. It keeps my legs elevated and takes the pressure off of my back. If she lays on her stomach a lot, it helps me to keep a pillow under my stomach as well...however, laying on my stomach is not comfortable at all for me. I really have to lay on my back all the time...and before my back problems, I absolutely COULDN'T do this. But it just helped so much.
Also, kind of a common sense back saver that I think everyone kind of overlooks is not bending over to pick something up...use your legs...use your legs to lift something as well. It helps a lot.
I'm definitely praying, and if I can help in any way, let me know!