[Weltterr]

This sounds like she is not properly supervised, and she is not properly trained. Giving a dog a whack is not the way to train her. She needs more attention to show her what to do, instead of just what not to do. And when she does the right thing - by your redirection, she has to be rewarded. If you don't make it worthwhile for her to chew on toys instead of doors, why should she choose to do that?

Many dogs who appear to have a poor attention span are really just confused over what is expected of them. Start reading up on positive training and start implimenting consistency in your actions, your words, ect. More consistency from you should result in better attention from her. Think about what you can do to make her training fun, since you say all she wants to do is play.

Until you have trained her properly, she should be confined when not being supervised. If she is not crate trained, then that is where you should start. Everything in a dog's life is good or bad - brings pleasure or pain. It is your responsibility to make good behavior pleasurable for your dog.

Since she is in obedience now, talk to your trainer about what you should be doing. (don't do anything that is punitive, however, and explain to your trainer that you want to use positive training methods.) Your dog's behavior can change, but it is up to you to show her how. And if you want a good relationship with your dog, you have to use positive methods for training.