Son by Four is a Puerto Rican Latin music group best known for the song "A Puro Dolor" and its English-language version, "Purest of Pain". The group was formed in Puerto Rico in the late 1990s and was created by Panamanian producer and songwriter Omar Alfanno with members Ángel López, Pedro Quiles, Carlos Javier Montes and Jorge Montes. The group first recorded Latin pop and salsa music and achieved its commercial breakthrough in 2000 with "A Puro Dolor", which spent... [more on Wikipedia]