That is one of my physical symptom and its caused by anxiety. Had a lot of stress lately so it came back. I have times when I'm ok but I'm on meds. I was really fine for awhile too and stopped (very gradually) my meds but unfortunately the smothering sensation was so bad I couldnt handle it. I felt out of breath, like I was going to really suffocate. Its horrible!
I had to upper my AD in the last few days because I started to really feel the smothering coming back on saturday and it was like that all day. Not quite gone yet but I can tolerate it. Its ups and downs with it but for me, when I get it, it wont go away until I take medications.
And I had all the tests done for my lungs. I asked my doctor a few months ago to check my lungs as I tought I might have asthma (we always try to find the rational explanation). Nope he said. No asthma. Ok, I feel better...till next time
Anyway, just know you are not the only one. And I'm glad I know I'm not the only one too. When it started 7 years ago, I ahve never heared of someone having what I had.I was convinced I had a deadly disease and was going to die. I'm still here today
Hang in there, I know its tough but just know its your anxiety doing that. And do whatever it is you need to do to feel better (meds, seeing a therapist, both or relaxation). It wont go away but will help you tremendously.
Hope you get better soon