I feel as if this pain is caused by a build up of toxins which are being extracted during cleansing. Drink loads of water to flush these out of your body. I have had shoulder pain during the Master-Cleanse as well as discomfort around my lower rib zone. I did a Liver Flush and it helped. I found it difficult flushing with salt water as recommended in the Master-Cleanse and think by not doing this regularly the toxins accumulated and caused the pain. The apple fast folk talk of shoulder pain as toxins are released. Hugs and encouragement, Nan.