I had similar symptoms. EKGs were fine. I don't recall jaw pain. I had an endoscopy after my heart was ruled out. The first scope revealed a hiatal hernia, GERD, & stage 4 esophagitis.
An esophageal spasm will mimic a heart attack. That's a possibility.
My GI doc wants me to be at 170 lbs. I'm also 5'10".
If it is your heart or if it is reflux, try to cut out the smoking.
Do any foods trigger your symptoms? Avoid eating too much, lying down after eating (wait 2-3 hours), eat slowly, and try to raise the head of your bed.
Avoid tomatoes, chocolate, peppermint, fatty foods, citrus fruits... and see if it helps.
The last two statements are to help GERD.
Try this for a bit and see if it helps. You may want to talk to your doctor about an endoscopy.
LapNissen Fundoplication, 8/9/13
GERD, Anxiety, Depression