There are several reasons for the vague pain in the right upper abdomen under the ribs: the first reason is cholecystitis and gallbladder stones, which are often associated with more pronounced pain after eating fatty foods and often require ultrasound and CT examinations to further confirm the diagnosis. The second cause is liver disease. When liver cysts, liver abscesses, or liver tumors appear in the liver, vague pains in the right upper abdomen under the ribs may occur, and CT and MRI are needed to confirm the diagnosis. The third cause is intestinal diseases. When there is inflammation or tumor in the intestinal tract, it will also reflexively cause vague pain in the right upper abdomen. The fourth cause is pleurisy and pleural effusion. When pleurisy or pleural effusion occurs, pain in the right upper abdomen under the ribs will also occur, and CT examination of the chest is often needed to further confirm the diagnosis.