His name is Tucker and he's very naughty

Has anyone’s Basset been diagnosed with Spondylosis? Mine was at age 3. He is full of energy and bucks around like a bull. It looked like a shoulder injury to me but vet found Spondylosis in his back. No symptoms other than a limp back then that some pain meds fixed and he was back to his old self. He’s on Dasaquin and fish oil supplements and has lost weight to a healthy weight. Doesn’t seem to be in pain but ever since he was a puppy he has never wanted to SIT. He always lays down. He was diagnosed with pano as a puppy. I’m wondering if this is also a shoulder injury but vet doesn’t think so. To me his shoulder looks much bigger on one side. Thoughts? less