My dog's hip bones are sticking out?

I have a 2 year old Shih Tzu who has his hip bones sticking out. When I pet him, I usually run across it. We feed him the amount our vet specified so I don't think we're starving him.

Whenever we bring out dog treats, he always stands on his back feet and will sometimes do it for minutes (We make sure he does a trick before we give him the treat but sometimes he feels like being stubborn and won't do it so he just continues standing like that.)

He also always runs to us and stands on his back feet when he sees us but refuses to let us carry him.

Is his hip bones sticking out normal? Is it because he's standing on his back legs too much? I'd really like to know in case it's something bad. Thanks!