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.