Dog peeing all the time in the house....?

I just adopted a 8mo old puppy from the local shelter about 3 days ago. He is said to be a Chi weenie (1/2 chihuahua & 1/2 datsun(weenie dog). He is a very sweet dog but the only problem I'm having right now is his peeing everywhere, ALL the time. Especially if you come near him to pet him or pick him up. I try rushing him outside but by then I've already been peed on. Sometimes it's just a little and sometimes it's A LOT. When I take him for walks he doesn't go and just follows me around, I know to praise him when he goes outside but the problem is he doesn't go! How can I get him to stop peeing everytime we come near him? And how can I encourage him to pee outside? I am trying to crate train him, and he has a set schedule on his feedings so is there something I'm missing?