Have COPD , lungs at 39%, heart back to 60% from congestive failure.

Trying to figure if breathlessness is from heart or lungs, looking for tips. Oximeter reads Oxygen Ok but not sure if I'm getting false reading as cold seems to mess it up and have trouble with pulse as well. Can be all over at times. Former smoker, recently quit. Stopped most heart medications as seemed to feel worse with. Some days Ok, some tired all day. Walking up inclines hard. Practice drums for hours, but getting harder and need to break a lot more , though I'm getting better if I say so myself. Use nebulizer and am advised to get Zephyr valves.