Having on/off chest pressure on left upper chest and sometimes sharp pain under/betwn both breasts. no history of heart/bp problems. ?

See your doctor : Although most chest discomfort in young people without risk factors is non cardiac in origin it would still be best to get a check up. Common reasons include chest wall musculoskeletal pain (costochondritis, muscle spasm, hiatal hernia and acid reflux w esophageal spasm. Stress reduction and relaxation techniques as well as reducing caffeine and citrus fruits and spicy foods might help.