Yes, HEARTBURNS is a Scrabble word!

Letter values in Scrabble US: H 4, E 1, A 1, R 1, T 1, B 3, U 1, R 1, N 1, S 1.

Is it a valid word?

HEARTBURNS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a painful burning sensation in the chest caused by gastroesophageal reflux (backflow from the stomach irritating the esophagus); symptomatic of an ulcer or a diaphragmatic hernia or other disorder