Hi, I took two hard punches to the left chest about a month ago, had chest pain for four days with difficulty breathing, had a heart attack on the fourth day-I have angina, and was recovering. I then got some flu bug or something set off my immune system-I have systemic inflammatory disorder, and then had difficulty breathing deeply with cough that produced really just little liquid, droplets, but when I coughed, it felt as if there was a little bag or sack being blown up in my lung? Could that be a collapsed lung?