The song "A Puro Dolor" by Son by Four is about a person who is struggling with the pain of a breakup and desperately wants their former partner back in their life. The lyrics express their deep longing and anguish, as they confess their feelings and apologize for violating their promise. They describe feeling empty and lost without their partner, and their days and nights are filled with nothing but pain. They ask for their fantasies and desires to be returned to them, and for the air that they need to breathe to live. The overall message is one of heartbreak and yearning for a lost love.

Son by Four is a Puerto Rican salsa and romantic ballad group, known primarily for their hit "A puro dolor". "A puro dolor" helped Son by Four win a gold record as well as receive four Billboard Music Awards (December 2000) and seven Billboard Latin Music Awards, including Popular Artist and Latin Song of the Year. The group soon recorded a new Spanglish version titled "Purest of Pain", and this version broke into the top 30, peaking at number 26 on the Billboard Hot 100. The album sold 315,000 units in the United States and worldwide.