I am not going to tell you to go to an OB class. But I will tell you that your dog does need some degree of training. Lucky for you its an easy fix so long as you are willing to work on the behavior problem.
What you need to do is make YOU the number one interest of your dog. This means carry high value items with you (favorite toy, treats, food). When your dog starts to pull you, STOP. Do not move, no matter how much your dog tries to pull you in another direction. Pull out that high valued item and distract your dog with it. Once your dog is distracted put them in a sit beside you. Continue this until your dog pays only attention to you and then continue the walk. IF you take two steps and they start pulling again, repeat. Eventually your dog will realize that you are more interesting than the lady across the street or the Dachshund hiking its leg.
Oh and this is only easy to do, so long as you want to put in the time and effort.
OH I want to Add: Threshold is very very important. Know how close to the trigger you can be before you get a reaction. If being a couple feet away from the trigger does not peek interest in your dog, cool. If they have to be a couple feet father from the target to get no reaction from the trigger so be it. Know your dog.
(There is nothing bad about an Obedience class; A good class will teach you how to bond with your dog so you can know what triggers it and how to work with your dog to fix them)