I have alot of experience in this area....have both shoulders with impingement and c-spine issues (nice, huh?).. .I've tried alot of stuff out there...
Been taking high potency glucosamine/chondroitin/MSM for years... it's helped *a little*, nothing earth-shattering...problem is, you need a high potency product and you have to take it for 2-3 months to start noticing anything and then continue to take it.
Aflutop injections work fairly well - 21 day treatment
Don't do de-ca for the sake of only relieving joint pain...the pain WILL come back once you're off.
I just recently ordered cissus powder, it's been recommended to me, so am anxious to try it.
As for diet, you should already be taking your omega's and healthy fats, they help with inflammation and joint health. I also throw in an unflavored gelatin packet into my shakes...read a while back that it *could* help with joint/cartilidge.