Hey Kurt, not trying to be nosy, but , I just saw where Max is a little under the weather in his hips, and hind legs.
My lab mix was having the beginnings of the same problem, we got him some "Pro-Pet Glucosamine Advanced Chronic Care". He now runs and prances around the back yard like he was a puppy again. He hasn't done that in , literally, years. Labs quite often get Displasia (arthritis in dogs), and Reggie had all the signs, and a big knot on his hip joint. I could tell a difference in two days, and now three weeks later, the knot is gone.
http://www.propetwebvet.com/catalog/prod_detail.php?petID=1&secID=1&catID=16&id=8
We got it at WalMart of all places.
Maybe it will help, and maybe it won't, but I thought I would throw it out there if there was a chance. What ever it is, I hope Max gets over it soon!