i also was short of breath, for about four and a half months. i was tested for covid too and was negative. also had chest xray, showed just slight scar, nothing of concern. my doc put me on two different kind of inhalers but they didn't help much. i have a heart condition so i also got an echocardiogram but my results were stable. i wish the testing could tell me what i have but at least they told me what i don't have. my doc suggested spirometry but with covid, i declined. if you can see a lung specialist, that would be helpful.

meanwhile there are things you can do to maybe try to feel better. from what i learned about our lungs from all the covid news, it said they are primarily in our back area. so i started to sleep on my side as much as i could. i would use pillows, blankets, anything i could find to prop me off of my back when sleeping. i also did some acupressure. Instantly Double Your Lung Oxygen Level (Created by Dr Alan Mandell, DC) - YouTube dr mandell has other videos about how to strengthen our lungs. gradually, i have gotten better. i am not sure if the acupressure has any downside but i only did it for a short while. there are also a lot of videos on different breathing exercises. i hope something will help you.