Ok.. there s a nerve from the top of the neck that runs up the back of the head (C-1 nerve). Problems in it cause pain in that location, often triggered by neck/head movement. Taste/smells are from the totally opposite side of the head (nose and the first cranial nerve that runs under the brain near the nose). A stretch to connect it to neck problems. X rays of the neck to establish the surgery didn t fall apart then physical therapy and/or traction and/or injections, pain manangement would be standard treatments. Nasal inflammation/infection/sinus blockage can cause changes in smell and taste, I cannot say in your particular case without an exam.