Dueles is from the verb doler, which means "to hurt" or "to ache". While often used to describe physical pain (e.g., me duele la cabeza - my head hurts), this song uses it in a deeply personal and poetic way to express emotional heartbreak.
By singing ¡cómo dueles!, the artist is saying "how you hurt me!" or "you are a source of so much pain." It's a powerful and direct way to express that the very existence or memory of a person causes a deep, constant ache, making it the central theme of this moving ballad.
Have you ever counted the exact days after a breakup? In "Dueles", Mexican pop sibling duo Jesse & Joy pinpoint the exact moment the sting feels fresh: "Hoy se cumple un mes que ya no me ves" ("Today marks one month since you last saw me"). Joy sings about paradise vanishing overnight without warning ("Sin aviso, nuestro paraíso nos dejó" ["Without warning, our paradise left us"]), leaving her with a memory that literally casts a shadow over her heart ("tu recuerdo me hace sombra al corazón"). She even makes a brutal comparison between physical bruises and emotional wounds: scrapes fade away, but this split broke her in two, beyond repair.
The real language gem here is the title itself. In English, you say "you hurt me," but the Spanish phrase "¡Cómo dueles!" literally treats the person as the ache itself: "How you hurt!" Joy takes this further with "me dueles" ("you hurt to me"), framing her former lover as a constant, throbbing sensation. By the bridge, she throws up her hands and tells the ex to go off, be free, and become a total stranger ("Sé un extraño" ["Be a stranger"]) so the pain can finally stop. It is a sharp, beautifully dramatic venting session that any English speaker nursing a broken heart will instantly understand.