I dunno - can't say I've had that experience. It does sound crazy. I wonder if it's just that you are more aware of your breathing now that you are quit and altho' you had the "problem" before you either didn't notice or just ignored it because if you'd really paid attention to it, that would have been too scary. Here's what I'm thinking - I quit CT one time when I was facing lung surgery...in the days preceding the surgery, I took walks everyday to try to exercise what I thought were already "dead" lungs ...weird thinking...anyway, I felt winded and as tho' I had no "air" - BUT when I went for a spirometery test (breathing) my lung capacity had increased so much that the technician was kinda wondering why I was even there. Furthermore, I had some other minor out patient surgeries in my past - not lung related - where my recovery period was tough and I was awful. This time - with just 2 wks. of no smokes before the surgery, it was like a miracle. Not that I didn't experience any pain, there was some, but the projected recovery period and the actual recovery period were VASTLY different. So, my guess is that perhaps you are just focusing more on your breathing and realizing how bad it is/was...I'm not an MD tho' so maybe I'm just "blowing smoke" - HA! Hope it gets better for you soon.
