I wonder if sleeping in a comfortable chair (recliner-like, or just large and soft), or a couch with high and comfortable arms to put your head on, would be less likely to trigger the pains and anxiety. Maybe being horizontal has come to be associated with your pains (mental). Or maybe being horizontal changes blood flow or breathing (physical). Worth trying anyway.

I used to use melatonin, worked pretty well. That was for shift work and daytime sleeping.