Hello, thanks for your question today! I am Dr. Drew, and I am a licensed veterinarian. I'll be happy to help you in any way I can.
From your description, I would be most suspicious of a possible spinal problem, in the neck or back,
usually caused by a bulging disc between the vertebrae.
I'm not sure if the anti-inflammatory medication that was prescribed was a steroid or a non-steroidal type of drug, but I find the steroid type to be more effective for managing this sort of suspected disc problem.
In addition, muscle relaxants such as DIazepam or Methocarbamol are useful in managing situations like this, as they will alleviate the spasms associated with pinched nerves.
Strict rest is typically necessary for 10-14 days as well.
If there is no improvement, x-rays can be useful but more often an MRI is what's needed to positively identify the problem in these situations.