I took terrible palpitations about three days after my first Pfizer dose. Had a couple of ECG's and blood done and it was fine. Nine weeks later, still getting palpitations, but took my second dose yesterday feeling quite apprehensive. Sore arm both times, weirdly feeling very wired in bed and not able to sleep, aching joints and muscles too. (Same as first time). Still worried re. palpitations. Get it checked out though if its worrying you. I dont think it really matters what vaccine we get, it seems everyone is different with respects to side effects. Not keen to take any more jabs now.