I'm going to die soon and I'm terrified?

I've had a couple of dreams that have felt so realistic like that, it's very rare, but it can happen. The pain in your chest was probably from the stress you felt from adrenaline...I wouldn't worry too much. I know how terrifying those dreams can be, and you might even feel that way for a few days after because they are so powerful, but like I said, just try not to worry about it. Go about your life as normal, and try to keep your mind off of it. If it makes you feel better, just approach things a little more carefully than normal...drive carefully, don't go out alone late at night, etc.