[6][8] "Heart Burn" is Sunmi's second song after "Oh Sorry Ya" that streamed through EQUAL X Spotify Singles, a project that aims to uplift female artists during International Women's Day.

[10] By the time "Heart Burn" was promoted, Sunmi announced a worldwide tour named Good Girl Gone Mad that started in Warsaw from August 14, 2022.

"Heart Burn" is described as a catchy dance and pop rock song, with an addictive melody that gives a "mysterious yet energetic vibe".

[13] The B-side "Childhood" is also a city-pop-inspired song from the 2004 movie The Notebook and has the same vibe as her other tracks like "Black Pearl", "Faded Love".

[12] To show the atmosphere of the music video, Sunmi dyed her hair orange and added some freckles on her cheeks via makeup.