Left side shoulder pain is an indicator of colon pain. I have look in my manual but it isn't straight forward because of the interdependence of the organs. You can't assume its just colon, gallbladder, liver it may be either or a combination. The following link describes better than I can about abdominal massage. However, it is massage specific web page but nonetheless makes the point about stress, posture and rhythmic activity. Liver-flushing gives the biliary a good start by non only cleaning out toxic elements but also exercises and strengthens the gallbladder. With lifestyle changes like reducing caffeine, stress and increasing natural habits such as good breathing it is much more.