Eddy,

Have you ever seen a chiropractor since your head hits? It is common for the neck to be injured during a concussion. It is worth checking out. Try to find a chiropractor who has specific experience with concussion.

Also, stress, especially the stress of an experience like you had, can cause symptoms to increase. Relaxing can be helpful. Maybe some soothing music and a nap or just quiet rest.

Hope this helps.