Hi CM296e4a (Marti) and welcome!
I see that you are a new member, having joined only an hour or so ago. We are glad to see you engaging with the community already by posting this (and your other comment), in the forums section.
I am hopeful others in the community will see your inquiry and respond by sharing their own personal experiences if they have felt this way.
I, too, have something to contribute. If you've been to see your physician and cardiac as well as other pulmonary issues (pulmonary fibrosis), have been ruled out, I was curious if the doctor offerred a suggestion as to why this is happening for you.
As a respiratory therapist yourself, do you have any thoughts as to why this is occurring?
Wishing you well,
Leon (site moderator asthma.net)