Hi Kimba-Welcome to the group!
Many will come along shortly with many questions that will help them lead you in a good direction. If your son hasn't been evalauted by a neuropshychologist, I would recommend finding a pediatric one in your area and having him testing. The do many tests to help diagnose different disorders. ODD rarely stands alone, he may actually have a different disorder that is causing him so much frustration, the he seems ODD.
My oldest and youngest difficult child have inappropriate outbursts as well. My oldest had to have his 2nd grade class evacuated once because he was throwing such a tantru. My youngest gets angry and refuses to comply with anything.
Have you heard of the book "The Explosive Child" by Ross Greene? It helped me understand my kids better. If you haven't read it, see if your local library has a copy and check it out.
My heart goes out to you. Again, welcome! More will be along shortly.
