The common upper neck injuries are what some call subtle neck injuries. They have minimal symptom to the uninformed. Not neck pain but more likely headaches and behind the ear pain and tension. Gentle upper neck mobilization without pursuing range of motion is helpful. Most important is your discipline to sleep with good head and neck posture. Strengthening can take months. C-1 and C-2 can be injured with just 4-5 Gs. A concussion takes 60 Gs or more.