When liver and gallbladder disease occurs, pain in the right upper abdomen can occur, and in some patients, it can also lead to pain in the right shoulder and back. The main reason for this is that the liver is located in the upper right abdomen, below the diaphragm. When liver and gallbladder disease occurs, if the diaphragm is involved, stimulation of the phrenic nerve can be reflected to the right shoulder and back, resulting in right shoulder and back pain. The reason for this is that the phrenic nerve emanates from the 3rd, 4th and 5th segments of the cervical medulla. Section 4 also sends out the dermatomal nerve down the neck and shoulder, so when the phrenic nerve on the right side is stimulated, it can also be reflected to the right side of the back of the shoulder.