Welcome to the forums!
It's possible your pain is due to fibro or another condition so you have to consult with a doctor before trying this. I've had similar problems with fibro, but also after a lung surgery. I wasn't moving around enough it turns out. After some physical therapy I had more muscle and it hurt less to lay down. It's possible some gentle exercise or physical therapy may help. I hope you feel better soon an get it all figured out it can be so frustrating not knowing 100% what is going on , but don't give up on feeling better.