In my experience, SOB - even with good saturation numbers - can result from anxiety/depression, exertion, increased CO2, reduced lung capacity, or any combination of these. If it continues, you may want to check in with your pulmonologist.

My Dr. put me on 0.5 mg of lorazepam twice a day for "air hunger". Between that and breathing exercises, my SOB has been reduced in intensity which for me at stage 4 is a great relief. Breathing exercises for me is concentrating on exhaling as much air from lungs to remove "trapped" air.

Hi SandraPeacock2, welcome. There are several possibilities on why. You need to talk it over with your pulmonologist. My Dr calls it "air trapping." With emphysema I don't exchange air as easily and I don't get all the air out of my lungs. Thus trapping some air in my lungs causing the SOB. I have to do pursed lipped breathing and some breathing exercises to clear my lungs.
But it was that conversation with my Dr. that helped me understand why and what to do about it. The most case is you are not exchanging CO2 and that can be dangerous for you.

I also am SOB with good SPO2 readings. Believe anxiety has a lot to do with it even though I'm not aware I'm anxious.

I have no answer. I have the same problem some days as well. I'm on O2 24/7 and still come up SOB some days. Sometimes I think it's anxiety???