5 yrs ago, my mama made it to the kitchen and called to me for help. She was rubbing her brestbone, and saying "I don't think this is a heart attack BUT..." A ride in an ambulance ended in her gallbladder being removed, the doctor gave her a bottle with 3 stones that were black and larger than silver dollars. All of her pain was concentrated in the heart area. She told me that she'd been having milder feelings of this on certain days ... she eats by a schedule ... slawdog on Wed kind of thing ... so what you're eating could be triggering gallbladder attacks.
An alkaline diet would be where I'd go with this, and liver flushing.