Explain Like I'm 5: Early Repolarization (30M)

Preface: I'm 30M, healthy, non-smoker. Had chest pain for years, intensifying a lot this past year, always been told it was anxiety. A few nights ago, Dr sends me to the ER because my EKG looked like I was having a heart attack. ER Cardiologist says no, I'm healthy, but my readings are typical for benign early repolarization. Psychiatrist says my lithium might be contributing.

I've asked for my EKGs from the ER, but they take a few days to be released. This question is more for general understanding.

Ask: I can't find any real wording or literature on early repolarization that isn't written for doctors. So I'm kind of confused as to what it is, if that's why my chest is always hurting (bc I'm otherwise fine), and whether I'll always have this chest pain, or whether I'm about to die suddenly because of this condition? All the internet info is a little over my head, or very scientific and process-oriented. So! Please educate me. Thanks in advance, y'all