I have pain in my right scrotum and my tummy is flabby. Ct scan shows no hernia. What could be reason for pain in my scrotum?

Sports hernia? A "sports hernia" is not a true hernia but laxity of the abdominal wall. Your discomfort may be due to irritation of the ilio-inguinal or genitofemoral nerves which reside in the lower abdominal wall and are at risk with weak abdominal wall musculature. An examination will help decide if this is what you have. Treatment is rest and ibuprofen.
Orchalgia. Chronic testicular pain is a common issue and many time we are unable to identify the source. If testing is all negative, then it is necessary to rule out musculoskeletal issues like a lower back problem. You should see a urologist who has experience in managing patients with chronic testicular pain and no identifiable source.
Epididymitis. It is possible that you may nave other causes too like torsion of the testes, varicocoele or mumps.
Orchalfia. Primary. Inflammation tumor an torsion. Secondary. Hernia, nerve root ( back).