Mental disorders are best diagnosed and treated by specialists (psychologists and psychiatrists) but often, especially if you belong to an HMO, you have to begin with a primary care physician.
An ADHD evaluation, if done properly, will be quite an involved and expensive process. If there is a university with a clinical psych program nearby they probably have an on-campus clinic where senior doctoral students will do the evaluation under the supervision of licensed psychologists. The waiting lists can be long but the cost savings can be tremendous.
People often make statements such as "everyone has that!" or "we are all ADHD". The mental health profession has clear cut diagnostic criteria for these disorder and although anyone can exhibit SOME characteristics of numerous disorders they don't necessarily have them.
Are these mental disorders overdiagnosed or has research just enabled us to identify them more efficiently/accurately? I don't know the answer to that but I know where ADHD was the diagnosis of the 90's it's now Bi-Polar Disorder. The student's who are referred to me for psychological evaluation are on average taking three psychotropic medications each and I've worked with a fair number of children as low as 5 years old lately.
I have been simply amazed at the severity of the problems I'm seeing lately.