Cholecystitis: This is an inflammation of the gallbladder, often caused by gallstones. It presents with right upper quadrant abdominal pain, which can be severe and constant, and may be accompanied by a palpable mass if the gallbladder is significantly inflamed.

Hepatic Hematoma or Abscess: These conditions can cause a painful lump in the right upper abdomen due to bleeding or infection within the liver. Symptoms can include pain, fever, and a palpable mass.
Pyogenic Liver Abscess: An abscess in the liver can cause pain and a palpable mass in the right upper abdomen, often accompanied by fever and other signs of infection.
Hepatocellular Carcinoma: Although less common, a tumor in the liver can present as a painful lump, especially if it is large or has ruptured.

Ruptured Hepatic Aneurysm or Arteriovenous Malformation (AVM): These vascular abnormalities can cause sudden, severe abdominal pain and potentially life-threatening bleeding if they rupture.
Perforated Peptic Ulcer: While more commonly associated with the stomach or duodenum, a perforated peptic ulcer can occasionally present with pain and a mass in the right upper quadrant if the perforation leads to a localized abscess.
Appendicitis (if atypical presentation): Although appendicitis typically presents with pain in the lower right abdomen, an atypically located appendix can cause pain and a palpable mass in the right upper quadrant.

Echinococcal Cyst: A parasitic cyst in the liver can cause a painful lump in the right upper abdomen, although this is more common in endemic areas.
Hepatic Hydatid Disease: Similar to echinococcal cysts, this parasitic infection can cause cystic lesions in the liver that may present as a painful mass.
Primary Liver Lymphoma: A rare tumor of the liver that can present with a painful mass, although it is much less common than other liver pathologies.