So last night my dog was found on he's back not moving. This morning he os shaking arching his back coughing vomiting and walking funny. What is wrong with him is he dying?

Why haven't you taken him to the vet? Only the vet (not us) can tell you what is going on.

Definitely take him to a vet if you haven't already. It sounds like his stomach may be twisted (which is usually fatal if not treated) or he may have some kind of intestinal block. Either way - get him to a vet ASAP! Good luck!