If you’re only using them under your head you haven’t truly lived yet. Under the knees (or between the legs if you’re a side sleeper) will take pressure off your lower back. Then you need a cuddling pillow, and maybe a prop up to lean your back against pillow. And if you feel like one more you can also put one on top of your head to block out any light or noise.

I keep one on top of my lower legs too, but that’s an emotional support pillow because that’s where my cat used to sleep before she passed.

It is amazing how much the pain from a bulging disc in my neck reduced when I switched to one pillow.