You have not told us much about your other possible issues. If the chiro did the 'twist the head and pop the neck' adjustment, I would discount it almost completely. It is too aggressive for the subtle upper neck injuries common to a concussion.

Gentle treatments by either an upper cervical chiro or a PT who knows how to mobilize the cervical vertebra without pushing for range of motion (this can undo any benefit) may be still worth trying.

If you neck is an issue, treatment must be followed with posture discipline. Any time resting or sleeping needs to be done with good straight head and neck posture. The ligaments need to tighten to hold the vertebra in proper position so the muscle spasms are relieved. Icing, especially after treatments is helpful. Check the Vitamins sticky at the top for info about upper cervical chiro and crushable ice packs.

Do you have any tenderness at the bony part behind your ears ? This often signifies muscle spasms from the neck.

I would not go near the Cymbalta for head aches. That is a months long experiment and off label. Head aches are a know side effect of Cymbalta.