Bile Duct Stones or Residual Stones: This is a common issue post-cholecystectomy, as stones can be missed during the initial surgery or form later. The presence of stones in the bile ducts can cause obstruction, leading to pain in the right upper quadrant (RUQ).

Adhesions or Scar Tissue: Post-surgical adhesions can cause bowel obstruction or compress nearby structures, leading to pain.
Hepatitis or Liver Injury: Direct injury to the liver during surgery or post-operative hepatitis can cause RUQ pain.
Peptic Ulcer Disease: Ulcers in the stomach or duodenum can cause pain that may be referred to the RUQ, especially if the patient has a history of peptic ulcer disease.

Hemorrhage or Hematoma: Post-operative bleeding can lead to significant morbidity and mortality if not promptly addressed. Although less common, it's crucial to consider due to its severity.
Bile Leak: A leak from the bile ducts can lead to peritonitis and severe infection, making it a critical diagnosis not to miss.
Pancreatitis: Inflammation of the pancreas can be triggered by the surgery itself or by a stone obstructing the pancreatic duct, leading to severe pain and potentially life-threatening complications.

Gallbladder Bed or Liver Bed Abscess: Although rare, an abscess can form in the area where the gallbladder was removed, causing localized infection and pain.
Sphincter of Oddi Dysfunction: This condition involves abnormal function of the sphincter at the junction of the bile and pancreatic ducts with the duodenum, leading to pain and potentially mimicking other conditions.
Mirizzi Syndrome: A rare condition where a gallstone becomes impacted in the cystic duct and causes obstruction of the common bile duct, potentially leading to jaundice and RUQ pain.