Question

I have a 7 year old male Maltese, (he weighs 15 pounds,) and periodically during the day he will walk with his back slightly arched, his head lowered, and if he tries to lift his head, he has to raise his right arm in conjunction with his head. Otherwise he still eats, urinates, defecates, and wants to go for walks. In other words, he is his same old self. I have felt him up along his back, neck, shoulders and belly, but I was unable to elicit a response, such as a yelp or other indication of pain. What could be causing his troubles? By the way, I had his anal glands expressed last Thursday because I thought that might be a contributing factor. One other thing, we recently moved into a house that requires him to walk up 6 or 8 steps. He has always been frightened of stairs, but he does go up these few steps. He doesn't like it much, and he takes sort of a final rush at the last two steps. Maybe that causes him discomfort? It seems to manifest itself after he lies down for a while.