There are a lot of different reasons dogs throw up. They can eat something that is not good or be contaminated with bacteria or other microorganisms or toxic ingredients. A sudden change in brand of food will affect some dogs. Internal parasites can cause vomiting. Diseases of the intestines, liver or kidney cause vomiting.
Is he still vomiting? How often is he vomiting? Does he always throw up food? How long after he eats does he vomit?
Let me know the answers or anything else you think might be related and I will try to be more specific.
I understand that you changed his food after he started to throw up. Changing food, in his case didn't cause the problem and it didn't fix it.
I would be worried that something was obstructing or partially obstructing the intestine. This is often a problem with puppies that eat socks and other indigestible things. Your dog is a bit older. Does he eat socks, toys, paper, rocks, etc.?
Do you know if he is defecating? If he is completely obstructed, he should not be passing much, but should also not be as playful as you describe. If he is passing manure, the intestines are not blocked completely.
If you know where he goes, you can find BMs and break them up to see if he is eating cloth or paper, etc.
We usually suggest withholding food and water from vomiting dogs. If your boy is drinking without vomiting, let him have water, but withhold food for a day and then give him only small amounts several times a day. This might give the intestines time to clear and recover from whatever.
If he gets sicker or doesn't stop vomiting within another day or two, you should get him to the vet for diagnostic tests (blood work, fecal, x'rays).
Thank you for your help. We will give him just water for a day then give him small amounts of food to see how he does.
Thank you again for your help.