Just look at this dreadful contraption. I found this on sale in a Calais pet shop yesterday. This is a prong collar. It is supposed to inflict pain on a dog so that it obeys your commands. The harder you pull or jerk the leash, the more pain is inflicted on the dog. It doesn't bear thinking about does it?
Modern research and modern training methods are always only kind, fair and reward based. These are not airy-fairy, namby-pamby ideas; the scientific research has proved that if you reward a dog for performing a required task then you substantially increase the likelihood that it will do it again. If you punish the wrong task, then you achieve nothing positive. Your dog will not learn how to behave if you punish them for doing something wrong. Your dog WILL learn how to behave well if you reward the correct behaviour.
If you are looking for a trainer or a behaviourist for your dog, then please look for someone who has recent professional qualifications and experience. Reward based training is the way forward. Rolled up newspapers, threats, shouting, pointing and prong collars are history.