Barky Dog Problems

Please do not get a bark control collar. Keep trying the positive reinforcement training. I'm so glad to hear that he is walked regularly, because that solves a lot. Find opportunities for praise. At times you catch him being calm and silent, praise him for it. He shouldn't get attention (good or bad) for barking, although I know that's easier said than done. A Shih Tzu isn't usually a problem barker, so I am sure you will see improvement.