this kinda sounds like when Zoey was a puppy. She has really bad agression problems like everytime we would move her. we scolded her and everything. So we were talking to the vet's about this and they said it sounded like a joint problem. He explained about how the puppy's joints are growing and she is jumping of beds and couches damaging her joints. This might be part of molly's problem since she is still growing and all.

Edit to puppies joints are still growing at 7 months??