I can appreciate your breathing problem. I’ve been treated for sleep apnea but I don’t have “obstructive sleep apnea”. My breathing problem seems to stem from my breathing related muscles just stop working in the middle of the night. I resume breathing when a big shot of adrenaline is initiated from the resulting low oxy level. And yes, my rib muscles at times tighten up and sometimes my back muscles, for what reason? One relief I’ve found from this Mayo website, is full deep breathing exercise. Before going to sleep, I’ll breathe full and deeply for 10 minutes or so. This seems to help a lot as I don’t wake as much in the middle of the night. I’ll even do the breathing exercise in the middle of the night if I’m really wide awake. While this may not be direct to your problem, the breathing exercise may well give you good relief. Do however, do get fully tested for a sleep problem, and hopefully a resolve will be found. ///