There are several ideas to help with this. Dog-training classes are the very best idea. You and you dog will learn exactly how to behave while on a leash so that walking with your dog is pleasurable and safe for all members of the family.
Dogs are rather insensitive around the neck by design - during a dog fight, most of the wounds are inflicted around the neck so there is not an abundance of sensitivity there to begin with. Many breeds have very thick, muscular necks, especially fighting breeds.
A device that really helps with dogs that pull hard is an over-the-nose head collar. Dogs care a lot more about pressure on their nose than around the neck. Before resorting to a medieval "pinch" or "prong" collar to control your dog, do consider an over-the-nose head collar such as the Gentle Leader or Halti Halter.
