Yes, I also had surgery first week of December(full scalenectomy, no rib resection) and failed "puff" test post surgery. Was on oxygen for a few days but that was it. I do still get random "out of breath" with only slight exertion on a daily basis. Too much talking seem to also trigger it. I keep forgetting to mention it at checkups. I haven't felt suffocating, sorry to hear you're getting such extreme symptoms.
That phrenic nerve doesn't like to be even "breathed" upon....it takes quite awhile to recover when irritated.

Marabunta