I've had a mild but persistent shortness of breath for over a year. I've been tested for literally every conceivable problem, and it all comes up clean. My respiration turns up normal by any clinical measure. My lungs seems clear as a bell based on at least 3 kinds of imaging. A gastroenterologist assures me it's not acid reflux. I am left with a conviction that it has to be use of nitrous before I realized how critical it is to filter it. I've tried menthol steam, some home respiratory PT where my partner pounds on my back while I'm tilted almost upside down. I've tried saline nebulizer treatments. I cannot get any relief. I was even completely honest with my pulmonologist about the nitrous theory, and he just shrugged and said he'd never heard of such an issue and it's probably all in my head. It's not. Has anyone else experienced this? I'm miserable and desperate. Thanks for reading.