Hi,
Welcome to the ehealthforum and I am really glad to help you out. Right sided upper abdominal pain can be due to peptic ulcers, irritable bowel syndrome, pancreatic causes, cardiac causes, kidney stones, pneumonia, musculoskeletal pain, lower rib fracture and malignancy.
Irritation of the nerves supplying this area can also cause pain. Irritation can be due to nerve compression or pinching due to any spine related pathology. In females, ovarian cysts can also cause pain in the abdomen usually in the lower part but it can be a referred pain in the upper abdomen also. So ovarian cysts also have to be ruled out. Confirmation can be done only after an ultrasound or a CT of the abdomen. Blood tests and an upper GI endoscopy may also be required in certain cases.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For an exact diagnosis, you are advised to consult your doctor. I sincerely hope that helps. Take care.