I have a sharp pain behind the ear on my skull happend a year ago i had concussion have had no other head injury since

Sprain: If your injury was severe enough to cause a head injury, it is likely you injured the ligaments between your head and your neck. The mucles of the neck attatch to the bones of the head and can be very painful until healed. A year is sufficient time to heal this pain with the physical therapy you have probobly undergone. See a physiatrist for more help. Consider prolotherapy injections.