@dcm8299 I had an endoscopy done many years ago and that's when they diagnosed me with GERD. I've been taking omeperazole ever since. I had some irritation in my esophagus. The breathing issue could be diaphragm related. I've seen people mention on here about the possibility of a weaker diaphragm that doesn't fully function for whatever reason. Almost like it doesn't fully expand when breathing normally. And as you mentioned in your recent comment, the air hunger issue still persists for most people even with normal O2 saturation.

Breathing exercises have helped me keep symptoms at bay most of the time, and moderate exercise also helps. I don't push myself too hard. You mentioned about feeling almost normal while running. I used to run a lot but had to stop because one day I came back from running and the air hunger got worse. So now I walk or lightly jog until I'm mildly out of breath, but not too much.

I would suggest diaphragm exercises, and I will look into that myself. It probably doesn't hurt to do some strengthening exercises even if that's not the problem. 🙂 Have you looked into other breathing exercises like the Buteyko method, or just breathing exercises in general to slow down the breath?