Hi @inde, Thank you for sharing your story and history. Sorry you're experiencing this. I know how distressing it can be especially since it's an involuntary and necessary function- breathing.

Though it may not seem like a good thing, it is a good sign at least that you have another symptom besides just the air hunger/shortness of breath sensation. I say that because with no other symptoms, it makes it more difficult to link pieces of the puzzle together, but with more symptoms you have a little more to work with.

Do you remember anything at all that happened during your walk when it happened? Can you remember any symptoms or anything strange happening even prior to the walking?

That's interesting about the chronic hyperventilation during your lung function test. That may be a symptom of whatever issue is going on as a way to overcompensate for the shortness of breath due to the potential obstruction. You might benefit from mindful breathing exercises to help slow the breath when you're not having bad symptoms.