^ aspirin, ibuprofen and diclofenac are all available OTC in places such as the UK and will help deal with the root cause, the inflamation. They're not a cure but may help with the pain as well. Just make sure you take it regularly at the recommended dosages, consistently as just a couple of doses might not help that well.
Cannabis does have anti-inflammatory and analgesic properties and so might be of use to you. I know many people that get relief using cannabis to treat arthritis, however you must be aware of the fact that some strains are better than others. Killersrkunk supplied by Underground Originals is a good strain for arthritis for example.
I would not use legal cannabinoid highs to treat any medical condition personally.
As for other legal alternatives, cherries (the fruit) have fairly potent anti-inflammatory properties and might help, as will chondroitin and glucosamine sulphate, which are available in all good health stores, as these are very useful for joint problems in general. They're quite cheap as well, so won't break the bank.
Hypnosis can be helpful, as well as massage and a healthy diet (don't underestimate the effect a healthy diet can have on your health).