I Have Had A Very Sharp Shooting Pain On The

I have had a very sharp shooting pain on the right side of my belly button it comes and goes every few months and lasts almost a week each time. Have went to the hospital and they ran test everything came back normal. I have a family history of tumors and worry it could be related. The doctors here don't have a clue what causes this. I haven't had a CT scan yet due to radiation. Any clue what might be going on. It's happened 5 times over the past 16 months.