Choledocholithiasis: This condition, which involves the presence of a gallstone in the common bile duct, can cause episodic pain in the right upper quadrant that lasts for several hours, matching the patient's symptoms. The absence of fever and jaundice does not rule out this diagnosis, as these symptoms can be intermittent.

Chronic Cholecystitis: This condition involves chronic inflammation of the gallbladder, often due to gallstones, and can cause recurrent episodes of right upper quadrant pain, especially after eating fatty foods. The patient's symptoms of episodic pain without fever or jaundice could fit this diagnosis.
Biliary Pancreatitis: Although less likely given the lack of specific symptoms like radiating back pain or elevated pancreatic enzymes, biliary pancreatitis (inflammation of the pancreas caused by gallstones) could still be considered, especially if the patient has had recent episodes of pancreatitis.

Acute Cholecystitis: Although the patient does not have fever or jaundice, acute cholecystitis (inflammation of the gallbladder, often due to a blocked cystic duct) is a serious condition that requires prompt treatment. The presence of tenderness in the right upper quadrant on deep palpation raises suspicion for this condition.
Ascending Cholangitis: This is an infection of the bile duct that can be life-threatening if not treated promptly. While the patient does not currently exhibit signs of infection (fever, jaundice), the potential for ascending cholangitis, especially if a stone is obstructing the common bile duct, makes it a critical diagnosis not to miss.

Other rare causes of biliary colic or obstruction, such as a biliary cyst or tumor, could also be considered but are less likely given the episodic nature of the pain and the absence of other symptoms like weight loss or persistent jaundice.
Hepatic artery aneurysm or other vascular causes of abdominal pain, though very rare, could present with episodic pain and should be considered if other diagnoses are ruled out.