Personally, I don't think they should have written "behavior problem" on the paper they gave you. That's totally non-descriptive and confusing for the average person, and that has a very negative connotation.

My guess is it means there is some sort of behavioral or emotional disturbance. For example, maybe you're bouncing your leg, talking very fast, or acting twitchy. I think "problem" should have been replaced with "disturbance," because "problem" makes it sound like you're misbehaving.