K.S.
If your son is having troubles in school then ask for a Child Study meeting. They should include a social worker, a school psychologist, and other professionals. Ask for a full workup to make sure that this is not stemming from an undiagnosed learning disability. If they say "It's just bad behavior," then say, "Whatever it is is affecting his education, and he is entitled to a Child Study. If is just 'bad behavior' and not an undiagnosed learning disability, then I want a Functional Behavioral Analysis and a Behavior Improvement Plan."
That doesn't mean that you don't take your son to a psychologist, but it does mean that you don't let the school give up on their responsibilities. In the meantime, the results of the school's evaluation would be excellent background information for the child psychologist you do take him to.
Good luck.