Hello, I am Dr. Peter a licensed Veterinarian. I would like to help. I need to ask you a few questions to be well informed and give you the best advise. There is no additional charge for information request.
1- Any vomiting or diarrhea?
2- Take a look at his gums and see if they are pink or pale?
3- Any known trauma or falls?
4- Any pre existing medical conditions?
1- Is he eating?
2- Did he get into anything or eat something out of the ordinary?
3- Take a look at his gums and see if they are pink or pale?
4- Can you take a rectal temperature?
5- Is he arching his back?
Is he eating?
Last question, and I will tell you what I think, give some time to type the answer.
How much does he weigh?
The symptoms that you are describing are consistent with musculoskeletal pain like a pinch nerve along the back or a soft tissue (muscle, tendon or ligament) injury. Less likely it could be abdominal pain. Ideally, he should be seen by a veterinarian. In the meantime this is what you can do:
1- Start him on one Aspirin 81mg every 12 hours with some food.
2- Rest him, limit all physical activity except to go outside to urinate and defecate.
3- Follow up with your family veterinarian. If he happens to lose the complete function to any of his limbs, that would be an emergency and have him checked by a veterinarian immediately.
Hope the above helps, if you have additional questions I will be glad to answer them.