sleeping on my back used to be difficult for me, too. I generally go to sleep on my heating pad, it has a timer to turn off after an hour. In the warmer months i just put it on a really low heat setting, however i am in CA where it is very rarely very hot.

I have found the use of a pillow under my knees really takes the pressure off my low back- you know how at the PT you lay on the table and they have the wedge thing that they put under you legs that is so comfy....well i try to mimic that feeling with a pillow. It also helps me be comfy enough not to want to roll over.

I also really like my buckwheat pillow. You can mold it exactly to your head, and then it doesn't move, you just stay supported in exactly the comfy place. I learned in feldenkrais how to do it correctly, to make sure your head is supported at a flat level instead of at an incline. I have found that i can mimic this with the buckwheat pillow. It can be sort of hard, though, so if i have any amount of headache (like 50% of the time), I have a really soft and fluffy goose down pillow which serves a very similar fun tion but is super soft.

Actually, the fluffy soft goose down pillow has been a favorite for years....especially when i have a bad headache, it just feels like my head is on a cloud.

i also find that my needs and preferences change over time, so no solution is one size fits all

i do like the rice sock, i have been meaning to make on of those but haven't gotten around to it.