@twitt99707 I do have asthma. Mine is the "e asthma" or allergic type named for the eosinophils that are a type of white blood cells that are part of the immune system. This makes my asthma worse when my allergies flare up.

I use air filters in my home that have HEPA and carbon filtration which help a lot. The allergies cause phlegm which blocks oxygen absorption in my lungs, and when allergies are bad or it progresses to a bacterial infection because phlegm isn't clearing, my heart rate goes up.

Honestly, both a heart problem and a lung problem can play into shortness or breath because they affect each other. Both heart and lungs have a degree of compromise because of your conditions and have lost efficiency in doing their jobs. It doesn't have to be only one issue being responsible for your symptoms or more at fault. Hopefully each specialist is treating you for your best outcome regardless of the finger pointing.

I know for me, part of my lung issues that are related to excess phlegm are physical issues of tightness, so my chest doesn't expand as well on one side because of a condition I have called thoracic outlet syndrome. If the chest wall doesn't move enough, the lungs don't move enough with each breath, so phlegm movement slows down. Allergies are producing too much of it trying to flush out the irritants, and it's like a slow moving muddy river. Often that can progress to a chest infection. My clue that this is happened is when I notice my resting heart rate go up.

I have also had excess phlegm production because of metals in my body causing an immune response. I know this because of improvements to lung function when the metals were removed and my breathing got so much better because there was less phlegm. The metals that were removed at different times were old dental work that was replaced with ceramic dental implants and teeth (no metals), and titanium plates from a fractured ankle that were later removed. I can manage my allergies to reduce my asthma. I know that exercise like walking that gets me breathing deeper helps me breathe better all the time and helps my heart too.

If you haven't looked at the Lung function groups here on Connect, you may want to do this as you can learn a lot. Here is a discussion that may be helpful:

Lung Health - "Mysterious shortness of breath: What has helped you?"
https://connect.mayoclinic.org/discussion/mysterious-shortness-of-breath/
Have you consulted a physical therapist? They can do an assessment to see if you have any physical issues like me that could be interfering with the mechanics of breathing. Have you considered using HEPA filters in your home?