What Causes Pain In The Leg And Headache With History Of ADHD?

Good Evening, I have a 8 yr old grandson who is diagnosed as a ADHD child and is taking 20mg of the generic of Addrol. My question is: he's been complaining off and on about his left leg hurting when he getw up in am or sometimes during the evening and he is having headaches approximately 2-3 times a week. It's not to the point of giving a children's aspirin and adter an hour or so he stops complaining. Shoulod I be overly concerned with this?