Muscle Spasms in Abdomen

Over the past year or so, I have been experiencing what I can only describe as what feel like muscle spasms in my stomach or abdomen.  They occur out of the blue but usually after I bend over, turn my torso from one side to the other or cough or sneeze. The pain is always in one of two places in my stomach - either lower left side or upper right side below my rib cage. The pain is excrutiating while the spasm lasts and nothing but time seems to alleviate it. When the spasms occur, I cannot move from the position I was in when it started. I don't have muscle spasms in any other part of my body. These can be terribly embarrassing, especially if they occur while I am talking to someone or walking - and can be dangerous as they have occured while I am driving.

I hope that someone here can give me some advice or clue as to what may be going on or if I need to have this checked by a doctor. Thanks!