Yes take her to Obediance class,that will help you a whole lot.And also ask the Obediance intructor about these problems.We had a Beagle and she had lots of chewing problems,like yours.But she got out of it by age 2. For the Pitbull,they were originally bred to be aggressive towards other dogs.You would probably need to socialize her some more,and dont let her lunge at people and at dogs.I use a training collar for my dog(aka Choke chain) and it works really well for pulling,lunging all that stuff.but wait until you go to Obediance class to ask you instructure,its kindof hard to explain how to use it properly.

Just PM me if you need some help still!