I bend the lower part of a pillow up to make a small "V" in which I position my neck. I find this comfortable, and a good way to prevent me from rolling my head

I bend the lower part of a pillow up to make a small "V" in which I position my neck. I find this comfortable, and a good way to prevent me from rolling my head in my sleep, which causes neck pain. I've also found that I can only sleep on my back with my legs crossed. I'm not sure of the ergonomic consequences of this position. I also have a very firm mattress, which just makes sleeping on my side untenable.