Sable is about 4.5 months old. Today she took a nap and was fine before but after she started limping. I thought it was just her leg fell asleep, but it went on for about an hour. She is eating fine and wants to play with our other dog just can’t. It seems like it’s in her front legs or shoulders. It’s only slight. All she wants to do is sleep when not around our other dog. Could this be growing pains or something more serious?