Yes, Ashley is right. My guys get a little sore too. It's harder on the little ones.
If it lasts more than two days then I would worry, otherwise it's pretty normal.
You can call your vet and ask, just so he could reassure you. Let Percy
rest,make sure he is drinking water, if he wants to skip a meal it's ok, but
starting tomorrow afternoon you should start seeing improvement, he
should start to feel better and not be as sore. This is from my personal
experience, of course some dogs react differently. If you ever have a
concern don't be shy to call your vet. I call mine with questions often.