Pain in the right side of the stomach, below the rib cage, can be caused by the following diseases: first, cholecystitis or gallbladder stones, especially after overeating or alcohol abuse, or eating too much fatty food. The typical manifestation is pain in the right upper abdomen, accompanied by nausea and vomiting, pain radiating to the right shoulder and back, and fever. In severe cases, stone impaction may also occur, manifesting as acute suppurative cholecystitis, and the patient may develop chills and high fever. The patient will also have chills and high fever. On examination, the right upper abdomen shows obvious signs of peritonitis, which requires prompt surgical treatment to remove the gallbladder. Secondly, diseases of the liver system may also manifest as pain in the right quadrant of the rib cage, especially in the acute onset of chronic viral hepatitis or the appearance of hepatocyte hyperplasia and swelling, the volume of the liver increases, and the liver peritoneum is also stretched, a common manifestation is pain in the liver area.