The habit of doing some form of exercise every day, even if it is only a brisk walk, can bring about substantial benefits. Before trying out any exercise programme you should definitely seek advice from a physiotherapist or doctor as many activities may not be suitable for your own circumstances. Most sufferers usually find that their pain decreases when they gain increased flexibility. This includes treatments like acupuncture and healing. Acupuncture has been successful for some people, although to my knowledge it tends to be less successful in treating RSI than other ailments.
Pain clinics exist for people who suffer long-term pain.
They teach methods of coping with pain, including the use of pacing techniques to help avoid the cycle of over use and under use. They also help the patient to understand the pain better and develop coping strategies to deal with it. Most RSI sufferers give them a glowing report. I would not really consider medication to be a treatment in itself. Painkillers and anti-inflammatory drugs play a valuable role treating some people, but they not a 'cure' and shouldn't be used as a means of working through the pain.