When we first got our lab, she hated to walk. Absolutely hated it. She would go half way around and then balk. It would take lots of encouragement to get her going again. I know something that you can try. Try taking some type of food to encourage your dog to move. Now don't give it to him till the end of the walk. that way your dog learns that walks mean food. I have seen folks use a box of cereal or anything that you want to use. Try it and see if it helps any
Dee