Keeping in mind that I've only been in medical school for six months (and the training is four years, followed by an additional three years of residency) so I have a long way to go. And I'm not comfortable yet trying to diagnose people even when they are in the clinic, so online it is infinitely more difficult (if not impossible). But there are a lot of things that can cause arm pain. Your risk factors are low, given the fact that you are so young, average and perhaps sub-average in weight, to have any major cardiac abnormalities. Have you seen a physician about these concerns? If there's one thing that causes the most health anxiety, I'd say it usually concerns cardiac issues. The best thing for you to do is visit your family doctor and express those concerns to him/her for your peace of mind.
Two normal EKGs is a good sign. If your pulmonary function test was normal too, that's another bonus. Sometimes if the palpitations are particularly impacting your life, the best thing to do would be to first get a baseline EKG. Eventually you might get an Holter monitor, which records your rhythm for 24 hours, or an event monitor, which is basically a little device you carry around that records your heart rhythms for a month; when you feel something funny, you press a button and they try to see if your symptoms correlate with any arrhythmia. These are easy and painless tests. But again, the first thing to do would be to explain your symptoms to your family doctor.
I was recently hospitalized for an arrhythmia that was due to dehydration caused by a chronic gastrointestinal illness, which causes electrolyte imbalances and can make an EKG reading look totally bizarre. But it turned out to be nothing particularly serious. Being young and fit with no history of early-onset heart disease is a pretty good indication that your heart is functioning normally. Palpitations happen, but are not always a sign of significant pathology. So go get checked out, and if you have normal results, you might not need any further testing.
Hope this helps, and I wish both of you the best. Keep us updated on your progress!
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