Hey CB,
Sleep Apnea is caused by your soft pallet collapsing and blocking your airway. At that point , your brain wakes you up enough to contract the muscles to pull the soft pallet back so you can breathe. The problem is that you leave the deep restorative sleep to breathe.
On your back , your soft pallet is right above your airway, that why its the worst position to sleep in.
I had sleep apnea 7 years before I was dx with
ALS. If you have not done so already look into a CPAP or BiPAP (better IMHO) to help you get some restorative sleep. That would be the first to do. You must be exhausted.
Glen