First off Briley that is child abuse, I must agree with Molly. And to answer your question: Everyone here is kinda right in their own way but its hard to post a question like this and get a straight answer from anyone because no one knows what you are dealing with. Even if they have a child who suffers from ADHD or other issues, all children are different.
I have 5 children. 2 girls age 3 and 3 boys who are 10,8 and 7. My 8 and 7 year olds are the my problems. Of course mine are so much worse because I am having to deal with the stress of caring for 3 other children at the same time. Not to mention the fact that my husband works night shift and sleeps all day, while I too run a business as well as take care of daily life, bills, errands the house and all. I know how stressful that this can be.
My worst one though is the 7 year old. He was very much like what you have described about your 4 year old. His problems were much worse once he started into school. Up until this point we had done everything that we could. Just like you are doing but it seemed to be pointless and I was so stressed at one point that I would just sit and cry with this stuff would happen. I felt like I didnt know if I was going to give up on myself. Once he got into school the problems multiplied. The tantrums, the disobedience, and my extremely smart child started to develop a learning disability. He is very intelligent but his mental state was interfereing with his ability to pay attention and of course that resulted in him falling behind. His teacher pulled me to the side and recommended that I take him and have him evaluated for ADD or ADHD. I did because I didnt know what else to do. In this day and time though ADD and ADHD are so commonly diagnosed that the childs real problems are never found. My son though was in danger of failing Kindergarden, so the dr put him on meds, my choice as to what drug so I did alot of research. It seemed to help him at first and he made it through Kindergarden but 1st grade was terrible and the dr put him on even more medication which then resulted in an opposite effect where that he had to have something else to help him to sleep at night. The problems persisted and he started to become violent to himself and others and had even been admitted to a hospital for hurting someone and threatening to hurt himself. Now we are talking about a 60 pound, 4 foot tall 7 year old. I had allergy testing done - still nothing. I finally found a dr who tested him even more for as much as he could think of, finally he was diagnosed with having a mood disordered and not ADD or ADHD. My 8 year old who has the ADHD takes a small dose of medication a day, he eventually grew out of his behavioral issues and really isnt that bad but he can sit still and pay attention long enough to listen to me. The 7 year for almost a year now has been weaned from the ADHD meds, he still takes medication to help him sleep at night because his mind works alot and he can make himself easily upset and it all starts back over again. You would think that he is an ADHD child but he has been taking a seizure medication as a mood stabilizer, its healing his brain and most time he is very good, In fact people cant believe how great that he is. In addition to this, he takes therapy 2 times a month, see a dr 2 times a month and has a counselor that helps him cope with school and other stress that may trigger his behavioral issues or tantrums.
This may not have answered your question but the truth is you wont get it from yahoo answers. See another dr, ask for blood test, food allergy testing and more. Take notes on what time of the day he is worse, is he eating at that time and what - change his diet up and his bedtime. I found that a very close schedule helps them to stay more calm. Find him a special place that he can leave from, child proof it and put up gates like in your living room. This way that he can be free and when he cant get into trouble it will be much easier. When he takes a tantrum - make sure that he is in that special location and lay him on the floor and let him cry and when he is done make sure that you pick him up and hug him ask him does he want to talk about what made him upset and help him to deal with his emotions. At age 4 there isnt alot that he can understand about himself, like why this makes him so sad. If a certain toy gets him angry take it away and never get it back. Some people on her might start to comment me rudely as well but I dont care. My husband gets aggravated with my 7 year old and wants to spank him sometimes but if I hug him he instantly stops.