Hello Jadilow, My understanding is that heart pain moves. It doesn't stay in one spot. It moves and that can be around the chest, and sometimes up an arm, through to the back, up into the neck etc.. Muscle pain can be sharp and in one spot. Try some moves that move the chest muscles around and breathe in and out deeply. It can cause sharp, localized pain when you stretch chest muscles.
I think you would know if you have reflux. It really feels 'digestive' and burns. Baking soda really helps. If you take it, any reflux should calm right down so that should tell you if it is reflux. Tums is okay too because it's just calcium. If you have Xantac, take it back to the pharmacy. They've discovered it's carcinogenic and it's been taken off the market.