I was having strange feelings in my chest about 14 years ago. I told my Dr about it and, after a checkup and an EKG she told me it was probably nothing and that I was too young (40's at the time) to be having any serious issues. Over the next month or so my symptoms became more frequent and more severe however I wouldn't describe what I felt as pain.
I went back to the Dr and told her it was starting to scare me. She hooked up a Holter monitor (portable EKG) and told me to keep a diary of the times and duration of my symptoms. This was on a Thursday and I dropped off the monitor on Friday with the diary book filled with entries.
On Monday morning my Dr called telling me I had to check into the hospital. I was leaving on Tuesday to go home for Christmas and told her I'd check in as soon as I returned. She said "You don't get it. You're checking in this morning".
I had a 95% blockage in my right coronary artery and got a stent placed to open it and, according to the cardiologist, was having a heart attack as they prepped me for surgery which was done the day I checked in.
Despite the fact they told me no damage had been done to my heart I've since had a regular heart arythmia. It causes a similar feeling to the one I had when this began and takes my breath away, sometimes severely. I take medications to try to control it.
About 12 years ago I had a minor stroke. I didn't go into the Dr until about 4-5 days later when the numbness in my left arm/face/side weren't going away. My Dr yelled at me but beside that, after the full gamet of tests, there was nothing to be done about it. I still have recurring symptoms from this when I'm tired.
I've had regular visits with my cardiologist ever since. My cholesteral and triglyceride numbers are almost spot on although my good cholesteral never gets as high as they'd like. Every few years I go through the entire series of tests (EKG, Cat Scan, Cardioechogram, Stress test, etc.) and every time I come up clean yet I still feel symptoms similar to those of both my blocked artery and stroke from time to time.
My point in all of this is that it's very difficult to know when and when not to call 911. A few weeks ago I lost taste in, and was getting numbness in the right side of my tounge. After calling my Dr then visiting the clinic at work I ended up in ER. After the full gamet of testing turned up nothing I convinced them to let me go. It turned out to be the onset of Bells Palsey (for my third time which thankfully resolved itself in a week).
In the meantime I haven't changed my lifestyle. I sill smoke, drink, eat bad things in moderation and don't excersise much. I figure one day I'll just keel over and die because I won't be able to decipher what's normal from what's not. Either that or I'll be riding in ambulances several times a year for nothing so I tend away from having these things checked on constantly.