Primary spontaneous pneumothorax
I had a large section of my left lung removed when I was 18. It just kind of popped. Released air into my chest and collapsed my lung putting pressure on my heart which in turn simulated a heart attack.
And let me tell you. That fucking hurt like hell.
I had to learn how to breath again. Spent two weeks in the hospital.
I did get a sponge bath from a hot nurse though...