Can anyone tell me why my AHI is getting worse?

Broke many ribs years ago and trained myself to sleep on my left side. It's so ingrained a habit now that I am unable to go to sleep except on my left side. I almost always awakened in exactly the same position until . . . the last several months when I have often awakened on my back! It wasn't concerning me because it actually felt pretty good except when I got up and would be really stiff for an hour or so. I am going to try the pillow prop to see if I can correct that positioning. I will do that for a few nights to see if my graphs change, but I am also going to read up on changing the lower pressure. If I don't see a reliable improvement from my pillow prep I will up my lower pressure. Thank you, Pugsy, I think you've ID'd the problem(s).