What breed of dog is he?Does he seem okay with you touching him anywhere, or is he painful all over?Any possibility of injury or trauma at all?Any vomiting or diarrhea that you've noticed?
Thanks for answering my questions.
The fact you had to elevate his water/food bowls and that he's holding his head in an unusual manner makes me think he's got some sort of injury in his neck or back. These kinds of injuries can happen very quickly in these little dogs. It could have been that he jumped onto or off of something bigger than he's used to, or he could have simply landed wrong, but the fact he's SO painful is a very big cause for concern.
If this were my dog, I would have him seen by an emergency vet tonight for an x-ray of his neck/spine. They'll check for things like disc disorders, bulging discs from injury or even spondylosis (a gradual narrowing of the spine that compresses the nerves). Even if they're unable to find anything, they'll be able to get him on some pain medications to help him feel more comfortable.
If there is no emergency vet in your area to see tonight, then you should just leave him be in any way he's most comfortable. If he doesn't want to be petted, then don't. First thing in the morning, give your regular vet a call and have them take a look at him.
However, if there is an emergency vet in your area...I'd get him there...just to be on the safe side.
I hope this helps.
I think for tonight, as long as he's acting mostly normal, you can keep an eye on him for the night, but you don't need to sit vigil with him. Just allow him to do what he normally does...dogs with injuries to their neck/back don't generally do anything that makes them feel more painful.
That being said...if he is crate trained, you may want to put him in there overnight, just so he doesn't wander the house while you're sleeping and possibly injure himself more.
Also, make sure you hit the green 'accept' button so I get credit for working with you. It won't end our conversation and I'd really appreciate it if you'd let me know how he's doing tomorrow (or later tonight if you need me!)