Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you today. I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your wee one’s situation, and wanted to help.
Again I do apologize that my colleagues could not aid you sooner. If you would still like assistance, can you tell me:
Did his vet trial him on any medication for this?
Do you ever see any lameness
, slowing, bunny hopping, or head hanging on walks or when he is moving generally?
Is he happy to let you extend any flex all his leg joints?
Is he comfortable in his belly?
Can you move his neck up/down/left right all the way without him resisting, yelping, or trying to push back?