When you have to pee really bad and my bladder feels like it's going to explode do you get cramps on your side??

Sometimes during the night or morning when I wake up I have to pee really bad and it feels like my bladder is going to explode. But my sides also cramp when I have to pee really bad. Then it goes away after I pee. Does anyone else? I don't understand why you would have cramps on your side when you have to pee really bad.