Can a Well-Behaved Child Have ADHD?

Ladies i need help. I dont have any experience with Adhd but I myself was diagnosed with Add and Odd as a child so i was on Ritalin for a bit. Anyway my son has tested positive for ADHD markers, so there Going to go ahead and test him for it. Has anyone had a well behaved child have adhd? I always associated it with bad behaved kids. When he was a baby he didn't cry, didn't have tantrums, never hit or bit anyone, hes always been good. But once hes around other kids he gets these massive energy Bursts, and its impossible to get him to sit still or anything now. Hes also now doing mindless things, like picking paint off my walls, and picking at my sunroof in the car.