I am not aware of a test for this. Strangely, I walked outside on a sunny quiet day earlier this week and tried to sense what was "off". I'm not too good at self observation like this but I did become aware that my chest was very tight and a bit sore. I took advil and tried a bit later. It was about the same but I noticed I stopped breathing. So I am a bit embarressed to say that I missed this and believe this was the primary issue. Since my original post to now, my chest is no longer tight and only faintly sore. I focused a little on taking deep breaths (which I thought I tried doing before) but the act of thinking about the need to breath is so foreign that this issue just cleared up. I hope this might help someone, or help someone who has SOB to rule this out. Thank you for the response!