Have you ever been tested for TMJ Syndrome? TMJ can be the cause of many pain issues associated with the neck, head, shoulders, face and even the back. I have TMJ for 30 years as a result of holding my mouth open to have my wisdom teeth extracted. I have had clicking and locking in my jaw ever since. At that time there was nothing anyone could do but I just discovered that there are now specialists that strictly treat TMJ. The symptoms can include migraine headaches, muscle spasms in the face and head, tight neck and shoulder muscles, sore face, ear aches, nasal congestion, dizziness, sensitivity to light, it's quite a long list. It might be worth checking out. Look for a specialist and sees his patients every two or three weeks on an ongoing basis. If he is just pushing a mouth guard and nothing else, keep looking.