I have shortness of breath, and this may sound crazy but I also have GERD.
I was in remission for acid reflux, but when my long covid showed up, my breathing became an issue. Anxiety caused me to focus on my breathing and that made it worse. I started back on Pepcid and I have much less pain and nausea in my esophagus. My breathing has improved. Also, I do breathing exercises as well. Hope you are able to get relieve. I know how uncomfortable shortness of breath can be.