The main causes of cholecystectomy with pressure pain when lying on the right side for more than two months include post-cholecystectomy syndrome or other diseases. 1. Post-cholecystectomy syndrome: After cholecystectomy, the patient has symptoms related to biliary tract diseases, which is called post-cholecystectomy syndrome. There are many reasons for post-cholecystectomy syndrome, mainly including intraoperative bile duct injury, excessive length of the leftover bile duct, stones in the leftover bile duct, narrowing or spasm of the Oddi sphincter. All of these factors may cause patients to experience pain symptoms two months after surgery. 2. Other diseases: generally refers to the right abdominal pain caused by other diseases excluding surgical factors, such as intrahepatic bile duct stones, choledocholithiasis, hepatic cysts, hepatic hemangiomas, duodenal ulcers, etc., which may also lead to the symptom of pressure and pain when the patient lies on the right side. The symptom of pressure pain when lying on the right side alone cannot determine the cause accurately, but also needs to be combined with the characteristics of the medical history and other test results to make an accurate judgment, it is recommended to clarify the cause of the disease under the guidance of a doctor.