I am a 35 year old male, non-smoker, non-drinker, not overweight, and in pretty good shape healthwise. A year ago I had way too much caffeine after being off of it for several months, and my heart rate and blood pressure skyrocketed. Since then, I have had continuous (daily) discomfort on the far left side of my chest, close to the armpit. Sometimes it radiates around the left nipple, then goes away. It is not painful, just annoying. I do not have trouble breathing. I have gone to a cardiologist and had MRI, EKG, ECG, treadmill, x-rays, and bloodwork done. All are negative for cardiac. Any idea what might cause this? I am leaning toward anxiety of some kind, though I have never been diagnosed with anxiety.