What causes a dull pain on the right side of the navel?

Dull pain in the right periumbilical region mainly occurs in the following diseases: cholecystitis, cholangitis, hepatitis, liver cancer, antral gastritis, duodenal ulcer, gastric antral cancer, colon cancer, ulcerative colitis, intestinal tuberculosis, and intussusception. Appendicitis is an exception, as the appendix is located in the right lower abdomen, with its surface projection at the junction of the middle and outer one-third of the line connecting the umbilicus and the anterior superior iliac spine. Since the appendix is a blind-ended structure, obstruction by fecaliths or impaired gastrointestinal motility can lead to secondary obstruction and infection, manifesting as localized pain. Severe cases may present with fever, diarrhea, nausea, and vomiting. Once diagnosis is confirmed, surgical treatment should be actively pursued.