I ended up taking Conner to a chiropractor (vet) for his shoulder limp. He has a wonky toe, back right, from an injury that didn't heal well. This throws his gait off, and eventually led to the left front shoulder limp. The chiro felt his shoulder, and along his neck and spine, found tension points, and made adjustments. It made a huge difference for him. We go once a month, and about the only time he limps on that shoulder (he has other limps for other reasons on other feet) is when he is due for his next apt. Her adjustment are always gentle, and other than an occasional muscle twitch/flinch, he never shows any reaction. He loves his chiro apts!
I wouldn't take him if he seemed in any way stressed or hurt. But, obviously, you have to get someone who knows what they are doing, and it isn't the right treatment for everything.