Fell backwards upside down on back of head. heard noise in neck upon impact. lot of neck pain, but can move neck and do activities. rest or go to doc?

Go to doc asap: The neck is one of those areas in which you could cause significant damage to the spinal cord if a fracture goes untreated. I am assuming all of the weight of your body fell in top of your neck which is not a good thing. You need plain films and additional flexion and extension views to rule out a listhesis/slippage. CT and/or MRI might need to be considered if there is suspicion for fracture.