Ouch! I've had a bit of bad luck with my lab too. She was in a lot of pain after our last hunt and we ended up at the vet. She has spinal stenosis, which is a symptom of some instability in the spine, most likely a herniated disc that is inflamed and causing her pain. He is on 6 weeks of strict rest (yes, the ENTIRE pheasant season here in Nova Scotia!) and then we'll take it from there. Of course I'm dissapointed about losing the season, but more imporantly I am worried about the long-term prognosis. We'll see when she's been rested and I phase her back into the last few weeks of the waterfowl season. I'll be bringing the boat so that I don't have to work her too hard if she doesn't seem up to it.
More to the point for your case (sorry about highjacking your thread!) I have had a great success with liquid "Metacam" for treating just about any painful ailment that a dog can have. It's expensive, but I swear by the stuff.
-Croc