Also not chewing your food well enough. All foods need to be chewed till it becomes a liquid before swallowing. What this does is allow the digestive fluids in the mouth to build up in the mouth before swallowing. Therefore counter act the acid in the stomach. Drink a glass of water on rising in the morning. Eat a good protein breakfast with fruit first. Start out with juice and some fruit, then an egg with bacon and whole wheat bread or toast. Coffee after wards if you wish. Chew your food well and don't drink water while eating. Water dilutes the enzymes in the food.
Some common causes are spicy foods, eating before bed, a hiatal hernia, pressure on the stomach (frequent bending over or obesity), stress, smoking, alcohol use and certain medications.
Heart burn is just stomach acid that leaks to the esophagus basically....nothing to do with the heart lmao