Bala perdida literally translates to "stray bullet". It's a fantastic Spanish idiom used to describe someone who comes into your life unexpectedly and has a huge, powerful impact.
In this emotional song, calling someone your bala perdida is a poetic way of saying they hit you with the force of love when you weren't looking. It perfectly captures the feeling of a sudden, intense, and unforgettable romance that you never saw coming.
This song is a straight-up plea from someone who can't move on. The singer fell in love easily, but now finds it impossible to forget the person who left. They were promised a life together—"Porque la vida me juraste" [Because you promised me a life]—but now that person is gone. The memory is so strong it just won't leave: "Tu recuerdo no se va, no se va, no se va" [Your memory doesn't leave, it doesn't leave, it doesn't leave].
He's not just sitting around feeling sad, though. He's actively trying to cope while holding out hope. He says he's training his broken heart, just in case he runs into his lost love again. He's so desperate he's willing to search everywhere, "De Bogotá hasta Buenos Aires" [From Bogotá to Buenos Aires]. The chorus is a desperate, repeated request for this person to come back and stay, not just for a night, but for a lifetime.