What Causes Pain In Left Arm?

hello, I just woke up with a pain in my left arm... it's on the bottom side and start at the armpit on down... it comes and goes every 15 seconds or so. Took two Bayer Aspirins with ginger ale, so I"m burping due to the bubbles . no chest pain , or nausea, but feel a little funny , maybe due to being tired...don't want to go back to bed... what do you think. I'm 57, my father had three heart attacks in his fifties, I workout every day with weights and run or walk two miles, I'm in good shape, but worry with my family history... what should I do?