The burn sounds like nerve pain. I get that a lot too. I can bare it most days but some days it is really bad and very distracting. I don't take anything for it but I take a lot of supplements that are supposed to be "anti-inflammatory". Do they work? I have no idea. I do know that I have been able to stand the burning most of the time. I avoid dairy and gluten, they are supposed to be inflammatory for some. I also take niacin. That acai juice or tart cherry juice is suppose to help as well. Kimber, our former moderator, says that her husband swears by the tart cherry juice. Although his nerve pain can be severe and then he resorts to powerful meds. I can't find the tart cherry juice and so I use the acai juice. I get that at GNC. I mix it with this healthy juice I mix each week. (no comments Sunny).
Others have tried cymbalta, lyrica and neurontin for the burning as well. You might want to give the cymbalta another try when you think you have seperated what is causing what (rebif versus cymbalta). Rhonda swears by the cymbalta for managing nerve pain.
If you are a fan/believer in foods and supplements that reduce inflammation just google that.