I recently had to write a set of articles on massage and pain relief associated with arthritis.
It has been years since I gave a massage (one very small part of training in my nursing courses was on massage techniques, I tried practicing on my dad and he had to have surgery 2 days later--apparently he fell when opening the file cabinet at work but my massage was blamed and I haven't had much of a drive to try giving more! LOL).
I do know several sufferers of chronic pain enjoy massage therapy to help them reduce the effects of chronic pain. Touch can help to break up the pain signals on their way to the brain, confuse the message a bit, and block the pain. If you have chronic pain you can appreciate this!
Before my back surgery I used to beg my husband and kids to give me back rubs as often as they would....they weren't trained well but at that point anything that would give relief was helpful.