Translation guide
A burning sensation in the chest caused by acid reflux. In Japanese, this is most commonly expressed with the noun 胸焼け (むねやけ), but related symptoms and expressions exist.
I have heartburn.
The common burning feeling in the chest or throat after eating.
The standard word for heartburn. Literally 'chest burn'. Used as a noun or with する to mean 'to have heartburn'.
I have heartburn.
I get heartburn when I eat greasy food.
Medical term for hyperacidity, often used to describe the cause of heartburn. More clinical than 胸焼け.
My heartburn is severe due to hyperacidity.
Medical term for reflux esophagitis, a condition causing chronic heartburn. Used in formal or medical contexts.
I was diagnosed with reflux esophagitis.
The sensation of stomach acid coming up into the throat or mouth.
A general discomfort in the stomach that may accompany heartburn.
胸焼け is the most common and natural way to say heartburn. It can be used with する (胸焼けする) or がする (胸焼けがする). Both are correct, but 胸焼けがする is slightly more common in spoken Japanese.
Do not translate 'heartburn' literally as 心臓のやけど or similar. It will not be understood. Stick to 胸焼け.
I have indigestion and heartburn too.