Some cats do get moer bony as they age. I have a 13-year-old that is just like a kitten. It might be time for her to have a geriatric blood panel done. They're about $200 where I live, but is a really worthwhile test to do. If anything is starting up you might be able to treat it inexpensively, as opposed to later when it's worse and more expensive.
Maybe a call to the tech at the vet's office would be an idea also.
"I have six locks on my door all in a row. When I go out, I lock every other one. I figure no matter how long somebody stands there picking the locks, they are always locking three." -- Elayne Boosler