Fortunately Jillee (and her son) from OneGoodThingByJillee.com have a recipe for a homemade pain relief cream free of chemicals and full of natural good stuff, including camphor oil, peppermint oil and eucalyptus oil (all available from this page).
It also contains coconut oil which has the added benefit of moisturizing your skin so not only can you naturally relieve pain, you can also nourish your skin!