My mother has a 1.5 year old tri-color male named Lewis. She just called to tell me she took him to the vet today because he's been whimpering in pain. He's been "moping" around and very slow moving. He gets brief spurts of energy in which he runs around and plays, and he's also eating fine. However, at times he will wince for no obvious reason and seems to focus on his right side. My mother said she pressed on his groin area (by his thigh) and the right side was very painful for him. She also caught him chewing at his right back end. My mom thought maybe it was a patella issue, but he doesn't seem to feel any pain when his legs are manipulated.
The vet's diagnosis is that Lewis has a back problem and needs to lose weight. He is 28 pounds and needs to drop about 8lbs. He's fed Royal Canin #25 and gets very few treats. In fact, the only treat he gets is a small dog chicken treat that is 100% chicken. The vet prescribed pain meds and another medication (my mom couldn't remember the name at the moment.) She is at her wits end on how to get him to drop the weight.
My concern is that this veterinarian once gave the very same diagnosis to my mother's Chihuahua (bad back, prescribed exact same meds). It seems like this is his go-to answer when he doesn't know what's really wrong. He's also a country vet and not very experienced with Cavs.