I agree with Ginger....My first thought is poisoning from an OTC Flea/Tick product.....But, a fall or jump could cause a Disk problem that would show these symptoms.....Also, a choke collar could damage a neck disk....
Either way, your dogs in trouble and needs to see a Vet immediately....Please let us know what you find out....It will help others that are reading this....Good luck...I hope everything turns out well......Karla
Does the groomer sedate your dog at all? You need to know for sure if they have used any medication of any kind on him. That includes any kinds of flea treatments, tick treatments, grooming products or perfumes. Also, did anything else happen, such as....he was picked up in a unusual way...leapt down from something awkwardly? etc.
You might have to think carefully how you ask these things as the groomer may feel you are accusing them of mishandling your dog. But you need to know if anything unusual happened.
Whatever you find out -even if they didn't use anything, then I would say he is feeling unwell, and the best thing would be to take him to be seen by the vet.