First, PLEASE get some serious self-training and/or do some major research into training dogs. You do NOT hit them with the item. You do NOT lock them up for the day (they end up bored, confused, no clue what's going on, scared, and basically a ball of emotions, and you've done nothing about the actual problem). This is why German Shepherds end up violent and attacking people, and end up with a bad reputation, when it's the human's fault for being totally unprepared and uneducated about how to handle a puppy. You need a consistent training program that is adapted to how a puppy learns and thinks, not just willfully striking out or locking them up. A puppy learns and explores with its mouth. It doesn't know that chewing is wrong, and really chewing is NOT wrong. Chewing the wrong things is wrong, so they need to be shown what they can and what they cannot chew. I also just got a German Shepherd puppy, and after 2 weeks she is doing beautifully. When she starts chewing on something that she should not have, I tell her sternly to "Leave it (in English, of course)," then give her something she is ok to chew on (like a toy). When she starts playing with her own toy, I tell her what a good girl she is.
Please. Buying a dog is a responsibility, not a game. Educate yourself. If your dog isn't trained correctly, they will not have the confidence they need to be a good, well-behaved dog. When a dog is raised wrong and ends up biting someone, THEY pay the price for their human's negligence. It's not too hard to get some training, and it's so fun, I promise!