Ella did the same thing, at about that age. The only thing I could figure out is that maybe she was laying on it funny when she slept. Could also be do to a growing puppy. Vet didn't find anything wrong with her, and she doesn't do it now.
But one time she did chew a chunk out of her foot pad once, and the vet had us put vasoline on it and keep it clean.
Hope everything is ok with your Ein.
Thanks so much for responding. We just got home from the vet a little bit ago. He gave her a real thorough examination and said nothing was broken or torn, and it wasn't her foot at all. He thinks she sustained a soft tissue injury from all the wrestling and playing I let her do at the dog park (we go a few times a week). He couldn't pin point exactly where she was injured or hurting, cause she would squeal wherever he would squeeze or poke her. He started squeezing and poking on other parts of her body and she would squeal then too. He laughed and called her a drama queen. He said that rest would heal her, and gave me some anti-inflammatory pain meds to give her twice a day. So no more dog park for us for a couple weeks. I don't have to keep her still, but no exercise, jumping up and down off the the furniture, or playing fetch. She's gonna be really broken up about the last one. Fetch is all time favorite. :( So a nice relaxing couple of weeks are in our future.