
stomach, esophagus, para esophageal hernia caused by, (
stomach being shoved up into the
chest due to be over weight, wearing belts or wastebands to tight, coughing to hard or to much, seizures), vegus nerve, gastro-paresis( suggish or paralized stomach)(very common ailment causes by diabetes, meds, surgery, aging). etc.
The best thing to do is to do a complete blood workup, endoscopy/colonoscopy, and get your heart checked. These are for starters. Then go from there.