Recent evidence suggests that pain in infants is not well-assessed, and that belief in its perceived occurrence is controversial. Pain in children is undertreated or ignored and its reported “validity” may be questioned, particularly in teenagers. Infants and children who experience pain in early life may show long-term effects in pain perception and altered neural responses that can negatively influence behaviors. Music therapists have the unique advantage of being in the dynamic moment of musical expression or resistance with infants, children, and teens. Using music as a psychotherapeutic informant—through assessment of crying in infants and clinical improvisation, song writing, and music visualization for children and teens—can inform healthcare professionals of the cultural and clinical aspects through the expression or repression of the pain experience. This course presents clinical examples of actual music and medicine cases that exemplify the influence of music psychotherapy as an informant of the disease experience. Musical expression as a means of treatment is demonstrated as a metaphoric mode of expression, comfort, and trust that can assist the child’s perception of fear and alter the cycle of pain and anxiety in acute, chronic, and procedural pain experiences.