Help!!!

Question
Hello! My name is Michelle and I recently purchased a 4 month old yorkie. I bought him from someone who purchased him from a pet store and she no longer wanted him. The thing is that he was being mistreated by her and her children, and now I think he is traumatized. First, I have been trying to train him to use the wee wee pads but he just uses the bathroom all over the house. Secondly, when I try to walk him he refuses to walk. He just lays on the pavement. Another thing is that he has begun to hump things, and I think he is way too young for that. Lastly, he is extremely hyper. He jumps all the over the place and when we try to play with him he is always tries to bite us. I dont know if that is his way of playing or if it is aggression. He never wants to listen to our commands. The only way to calm him down is by locking him up in his crate/cage. I dont know what to do. I am getting frustrated. Please tell me what you think should be done.

Answer
I think you should get him in to a class with a positive trainer really soon.   You have multiple issues and need some guidance on an ongoing basis for a little bit.  A lot of pet store dogs are a night mare to house train, but it can be done.  The key is to supervise the dog whenever he is awake (you can tether him to your belt with a leash - that keeps your hands free), take him to the approved spot outside or the wee pads frequently, reward him when he does his business in the right spot (and use the same words for the same functions all the time, like "go pee" or "hurry up"), plus never scold for accidents (haha, they are your fault for not supervising).  The key is to prevent any mistakes, so that he gets used to going only in the right spot.  
You should not use a crate as punishment - this dog needs training or he won't learn anything except that you are unpleasant, which I'm sure is not what you want.
Yorkies are smart, it's just that many people spoil them or think they don't need training, which seems to be what happened with this dog's previous owners.  They do well at clicker training, so if you can find a clicker trainer in your area you may be amazed at the progress you can make.
Dogs are not born knowing "commands" (I prefer to call them cues or requests), and if he has not been trained, he doesn't have a clue what you mean:-))
There are some free lessons at www.clickerlessons.com that I think might help you enormously.
When he bites at you, simply turn away as if he was poison - say nothing, don't move, and don't push at him.  Once he is calm, then reward him.  Repeat ad nauseum, so that he begins to realize that you will NOT play with him if he is rough with his mouth or being a jerk.
This is an energetic breed, but they don't have to be "hyper" - the more training you do, the better things may get.  Also, you can try to use "interactive dog toys" to give him some mental stimulation, as that tires dogs out, too.  If you Google that phrase, you should be able to find some online.  Also, once you get the basic cues down, you might want to try a sport, such as agility.  There's a group called the Teacup Dog Agility Association that even runs competitions for small breed dogs!