Shoulder and harness problem

Since Chimera has to be pottied on leash even in the yard, I got him a new harness that is easier to put on and take off. I can't keep a harness on him all day because it makes his fur mat within 24 hours. (This dog could spend all day sleeping at home and still end up with mats.) The one I got was the Ezy Dog harness:

I knew from a Chris Zink seminar I took a few years ago that having a strap go horizontally across the dog's shoulders isn't good for them, but I thought that for just his short walks it would be okay. I was surprised when I took him in for a chiropractic adjustment a couple of weeks later and his shoulders were VERY sore. He growled and snapped at Dr Wallace much more than ever before. She asked, "Has he been pulling himself up with his front legs onto something? Or pulling in a harness?" OOPS

Fortunately after adjusting his atlas/C1 (at the top of the neck/spine) and massaging his shoulder muscles, he calmed down considerably. And the Ezy Dog harness went into the donation pile.