Hey Cheryl - MO and RO said it was radiation induced fibrosis of the spinal cord - very common to appear 3-6 months after the end of radiation and should last approx 6 months. Range of motion - essentially stretching the cord itself through neck flexion is supposed to help limit the stiffening of the spinal cord. It's kind of a freaky feeling but now that I know I'm not doing permanent damage to my spine with each movement the freaky feeling, at least, isn't scary anymore!