Excellent advice...and if it's warranted, you can wear a Holter monitor for a few days to two weeks to catch the activity of your heart.
Without it being caught no one can say for sure what you are feeling. You may have some sort of transient block or you could be having ectopic beats. Considering you have muscle pain I wonder if some of your electrolytes are a bit low. I would go and see a GP and get a full blood panel and see if you are deficient in magnesium or potassium or if any other underlying issue show up. A lot can be seen in a blood test. If it turns out you have simple ectopic beats, pacs or pvcs, in a healthy heart they are not considered dangerous and are actually fairly common though most people don't feel them. So I would say get a full blood workup if you haven't had one already and maybe try some supplements to see if that helps your aching muscles. Take care.