Agonizando is a powerful and dramatic word meaning 'agonizing' or 'dying'. It's the present participle of the verb agonizar, which describes being in the final throes of death or extreme pain.
In this classic heartbreak anthem, the singer uses the word to describe his emotional state with the line "Agonizando, muy lento y muy fuerte" (Agonizing, very slowly and very strongly). It's a vivid, unforgettable word that perfectly captures the feeling of being completely overwhelmed by 'puro dolor' (pure pain).
Have you ever dialed an ex when you knew you really, really shouldn't? That is the exact mess kicking off "A Puro Dolor" by Puerto Rican pop group Son by Four. The singer breaks a promise not to reach out, admits he knows she is with someone else right now, and confesses he just needed to hear "tu respiración" ("your breathing") for a second. He wants to pretend he moved on, but drops the classic Spanish proverb "con un dedo no se tapa el sol" ("you can't cover the sun with a finger"). It is a colorful way of saying there is no point hiding something huge and obvious: he is completely miserable.
From there, he piles on the drama without holding back. He literally begs "devuélveme el aire" ("give me back my air") and claims he is agonizing in slow motion. Daytime feels like getting lost ("las tardes son un laberinto" ["afternoons are a labyrinth"]), and nighttime tastes like sheer grief ("a puro dolor" ["pure pain"]). Calling someone up just to demand they return your will to live is undeniably dramatic, but singing along to this kind of shameless heartbreak is what makes Latin pop ballads so addictive.