It sure sounds like you need to seek treatment for your neck. You may even need help with your shoulders and upper back. You would be surprised how a shoulder/upper back injury can cause a myriad of problems. My whiplash/head injury cause me to have esophageal spasms.

You said "My doctor seems to think I should be beyond the system of the concussions" This tells me your doctor is not very knowledgeable about concussions. Yes, the vast majority would be resolved by now but definitely not all. Up to 15% have delayed recoveries.

A physiatrist (Physical Medicine and Rehabilitation MD specialist) may be helpful.