Hi Tam,
Timely message.
I've had similar episodes for many years now, stabbing pain through chest, TIGHT chest, trouble breathing except VERY shallow breaths. Of course that leads to lightheadedness and who wouldn't have anxiety/panic about not being able to breath?

It was bad enough last week that I spent 5 hours in the ER last Wednesday night(Thanksgiving Eve) getting PEs(pulmonary embolism) ruled out. Mostly waiting for a chest CT. I also had been on a long plane flight Monday night so that added to my concern for PEs. This was my 2nd trip to the ER for this(first was 2 years ago), although I get the breathing issues to some degree almost daily.

In my case I've pretty much decided it is nerve irritation triggering a muscular response. Now that I can recognize it I do everything in my power not to let anxiety escalate the condition. I would guess the bad air is your trigger, muscular first, the resultant nerve irritation really kicks up the muscular tightening.

For me, the nitro didn't do a thing, the EKG was clear( as well as one 2 weeks ago), oxygen helped get my 158/108 BP back to its normal 117/78, and resting HR from 120 back to 59. Blood tests ruled out any heart enzymes, everything else normal.

Feels like broken/sore ribs for several days...taking it REAL easy. I attribute my lack of BM to the narcotics...I really try to up my already decent fiber intake whenever I take them. ;->