Chest Pains - No Diagnosis?

I didn't know where to put this, because I guess it could go into 5 or 6 categories.

I've had this issue for awhile and I'm getting rather frustrated with my doctors' inability to diagnose it. BTW, I am a 32 year old male.

2 months ago I started getting chest pains. Bad tightness in the chest, some small shooting pains, but generally just very uncomfortable. These pains happen more often when I smoke, but they're always there. Nowadays it just feels like someone is sitting on my chest. I don't have bad shortness of breath, though, which is strange.

I initially thought it was a heart problem. (I've had lone atrial fribulation once). That scared me, obviously. I saw a cardiologist and they ran me through every test imaginable- stress test, ekg, 48 hour monitor, blood work, echo, you name it. Everything came back fine. The cardio did notice that I am in tachycardia (fast heartbeat) more than 40% of the time, but didn’t think much of it and didn’t think it was causing this pain.

So I went back to my physician, got a chest X-Ray. That came back normal. The doctor did say something about emphysema, but he then did a breathing test which I passed and did real well on (especially considering I smoked). He then said something like "they just thought it was emphysema because of your frame". (I'm rather tall and skinny).

The doctor also thought it may be gastro-intestinal, gave me meds for that. That didn't help, and I don't believe it is anyway.

Emphysema seemed crazy for a 32 year old, but I quit smoking anyway. I've not smoked now (other than a slip here and there) for 3+ weeks. But that doesn't help. The chest pains/tightness is still there. Maybe it’s the lungs, maybe the heart, maybe gastro-intestinal… I have no idea.

There's nothing worse than when a doctor says they're at a loss, and that’s where I am.

So I'm opening it up to ideas/suggestions.