In my experience the ash/smoke from a blunt or bong hit is what causes the shallowness of breath (and associated chest tightness) but not necessarily pain as I have yet to experience chest pain.

Another issue us mixing weed with alcohol - crossfading is generally not a good idea. Weed and coffee also gave me the feeling of chest tightness and anxiety.

I suppose a control for me was when I had herb via edible form (THC oil). I experienced no chest tightness or anxiety.

All the symptoms of chest tightness, shallow breath and severe anxiety usually subside within a day or two, and stay away as long as I don't crazy smoking blunts/bongs or cross/mixing THC with other simulant/depressents.

So to sum up: if you're experiencing anxiety or chest issues a) cut all intact until you return to baseline or b) cut out the additional sources of stimulation for the body on top of the THC - that's the dust/particulates from the smoke, and mixing with coffee/booze.

Good luck,