I was suffering air hunger issues that would lead to a severe panic attack. At first, I was sent to do a stress ECG, which I was unable to complete. This led to a lung X-ray and I was found to have Interstitial Lung Disease. Rule out any issues with your lungs as my blood/oxygen saturation was sitting at 81% and when I walked it was dropping to 61%. This had been overlooked for I am guessing a year or more as it kind of creeps up on you and you adapt.