Lastimas comes from the verb lastimar, meaning 'to hurt' or 'to wound'. While 'hurt' is a common concept, the way it's used in this song is particularly poignant and central to the emotional core.
In "Me Lastima," the singer repeatedly emphasizes how the memory of a past love continues to inflict pain, even after the relationship has ended. The phrase "me lastimas" (you hurt me) isn't just about physical pain, but deep emotional anguish caused by a lingering memory, making it a powerful and relatable word for anyone who has experienced heartbreak.