Lots of things are claimed to cure joint pain but I think a lot of it depends on why the joint pain exists.
Vit C is essential for collagen production, collagen is the main component of tendons/ligaments which hold the joint in place, they get stretched/damaged the joint gets sloppy and wears away at cartridge causing damage. Boron (many sulfur elements actually) also play a role. Then you have pain from nerve damage as seen in various B deficiencies as well as claims by those such as Dr Hoffer who treated tons of people for crippling Arthritis with high dose niacin.