Tremors may occur due to an issue in the brain that affects the nerves controlling your muscles. Internal vibrations may stem from the same causes as tremors. The shaking may simply be too subtle Also, I am rather worried about brain damage from these. case in point, I was half asleep last night when my arm swung up and hit the pillow I was resting my head on. Note that it did not hit my head, but i felt a strong vibration move through the part of the head that was resting on the pillow (pillow is a little bouncy). YOVDR.