Overdose - Long-term aftereffects of X overdose

[ConcernedForHealth]

SWIM had an experience about 1 1/2 years ago which sounds like an X overdose and possible mild heart attack. A "collapsing" feeling in the chest and serious pain. He didn't go to the doctor, but had pain in his chest all night and since then has had recurring discomfort in the chest and headaches. It comes and goes but tends to manifest as a tightness and dicomfort which kind of moves around in the chest (i.e. not always on left or right side). Sometimes while sleeping SWIM has to lay on his back because it's too uncomfortable otherwise. Sometimes has spasms in chest while trying to sleep. It's mellowed out over time, but it's been over a year and it's still pretty bad at times.

Doctors have tested for proper heart function etc, and found nothing wrong. Anyone ever heard of anything like this before? Sometimes it's really disconcerting (being in the chest and all) and has led to a couple panic attacks. Like I said, the doctor hasn't found anything wrong, but there's definitely something up. Maybe psychosomatic somehow? Or brain damage of some sort? It's definitely a very real physical sensation in the chest though.