My Wilson has the same problem.
My Boxer Wilson has had pretty much the same problem for a while now. Vet put him on anti-inflammatory also and said keep him on it and on strict excersize rest for 3-9 months (x-rays showed nothing and neither did palpation so she had no clue what it was and how long recovery would be). After a couple months I got tired of him not getting better, so I decided to go see an orthopedic specialist. They basically specialize in all those lameness problems. She was able to figure out that he has bicep tenosynovitis. Basically his bicep muscle tendon is strained. It's not serious enough where he needs surgery thank God, but he will need to go through physical therapy.
He just started his aquapuncture yesterday. It's kind of like acupuncture only they inject a liquid into the acupuncture points, and don't leave any needles sticking in. The vet/physical therapist (this is a new person now, not the orthopedic specialist, but they are all in the same place) said it gives a prolonged/more lasting effect on the points than acupuncture. The liquid (I forget what was in it exactly) helps with pain relief and aids healing.
He will be doing aquapuncture for 6 weeks, and also ultrasound therapy for 3-6 weeks. This again offers pain relief, increases blood circulation and aids in healing by bringing up nutrients within the body to that area (I'm assuming with the increased blood flow there).
Okay lastly, she put him on supplements (omega 3 fatty acids and another one called ligaplex) and he'll also be doing hydro therapy in about 3 weeks once she thinks he's getting better and is up to it. He'll basically be running on a treadmill in a pool. Being underwater takes about 80% less pressure on the muscles, joints etc. Wilson is scared of water so we'll hafta see how he does lol, they said they have helped fearful dogs get over their phobia. But if not there will be other things they can do with him.
I was told they have treated several dogs like Wilson and they all got better! And the prognosis is about 8 weeks, but maybe up to 12. It's not gonna be cheap, I worked out it will be over $1000 for sure and I have already spent about $600 just at this place for x-rays, consultation fees etc. But it's totally worth it to finally see my baby get better and get back to the dog park and his fun active life.
I hope this helped and I hope you can get some answers with a specialist like I did. I'll keep you posted on how Wilson does.
p.s. Oh and one thing to keep in mind, if you had some financial worries like I did, a lot of specialist places tend to offer CareCredit.
Val, mom to Wilson
(Mr. Wilson, Wils, Stinky, Silly Willie),
Flashy brindle male born 06/28/04