Possible pulled shoulder or neck muscle

My poodle Rudi, who is almost 11 years old, has apparently done something to himself that is causing him to yelp in pain when he moves certain ways. I've checked him out thoroughly and he's tender on his left neck/shoulder area (trapezius area in human). I recall last week he was wiggling on the bed on his back like a puppy and just playing around and I think he may have pulled something. What do you think? I've been giving him Rimadyl left from another of his vet visits. It hasn't expired yet. How long do you think I should home treat before going to the vet? He is eating and going to the bathroom normally. He can even shake, as dogs do. Thanks for any advice

Poor Rudi Think I would take him ASAP, just to be on the safe side, hope he's ok

One of my guys had the same symptoms. Turned out it was a pinched nerve. Before I took him to the vet, I was manipulating him to find out where the pain was coming from. We thought it was the shoulder but turned out to be a pinched nerve in his neck. The pain traveled down making it seem like he was in pain in a different spot. X-rays would be my advice.

Thank you both for your advice. When I got home from work yesterday Rudi really was not himself so I took him to our vet clinic for a check up. It appears he has a pulled muscle and/or pinched nerve. Of course, at the clinic, he acted like nothing was bothering him They gave him Rimadyl, Tramadol, and a muscle relaxer. He's acting much more like himself this morning (Rudi is the red guy in the middle of my avatar picture)

he's gorgeous!Great to hear he's doing well