The right side of the belly button hurts when lying down, which may be caused by appendicitis, diffuse peritonitis, urinary system diseases, female gynecological diseases, liver and gallbladder diseases. 1. Appendicitis: inflammation of the appendix leads to pressure and rebound pain on the right side of the navel when lying down, which can be accompanied by nausea, vomiting, fever and other symptoms. 2. Diffuse peritonitis: the peritoneum is infected, triggering an acute inflammatory response, resulting in pain on the right side of the navel, and the pain is obvious when lying down. 3. Urological diseases: for example, the right side of the ureteral stone, the right side of the kidney stone acute attack, resulting in the right side of the navel pain, lying down when the pain aggravated. 4. Female gynecological diseases: such as right salpingitis, right ovarian cysts, endometritis, etc., resulting in pain on the right side of the navel when lying down. 5. Hepatobiliary diseases: such as cholecystitis, gallstones, chronic hepatitis, cirrhosis, etc., can appear in the right upper abdominal pain, lying on the pain aggravated, accompanied by nausea, vomiting and other symptoms. The right side of the belly button hurts when lying down, should be as soon as possible local clinic, clear diagnosis and treatment.