Assuming your DR is right, and you are as healthy as an ox, you may just be too tense behind the gun?? Not saying that you are nervous or anything, but if your scope height is too high causing you to not be able to comfortably rest your cheek on the stock, or you are trying make super small adjustments while getting on target without using something like a sandbag to do so, or maybe you are just holding your rig too tight. I could easily see how any of those would create you to shake a little, then all of a sudden youre playing mind games with yourself and end up shaking like hell. If you don't do so already, I would try getting a cheek piece and firing out of something like a lead sled. A set up where you are as relaxed and comfortable as possible. If that doesn't work, I would get a second opinion from another DR. Have you ever been tested for Hypertension, Anemia, diabetes or an inner ear problem???