I experience pain in my chest that radiate left arm and shoulder, 9month ago an internal doctor said i have mitral prolapse.is these are related?thanks

Not usually : Mitral valve prolapse is a description of how the two leaflets of the mitral valve close. If the leaflets bow into the left atrium that is prolapse. Sometimes the valve can leak because of the prolapse but not always. Prolapse by itself should not cause chest pain. The pain you describe could be anxiety, musculoskeletal, or coronary artery disease (unlikely in 20 y/o woman). See you doctor soon.