The over-stimulation is VERY common. I doubt a diagnosis if DAI vs simple concussion will change your treatment options. The treatment protocol is usually to treat the symptoms, not the diagnosis.

Lack of sleep can make over-stimulation more of a problem but many of us have over-stim problems even though we get adequate sleep.

Tinnitus is also a common symptom. I would be very hesitant to take on surgery for tinnitus unless there has been a solid diagnosis of an issue treatable by surgery. The side-effect risks from Microvascular decompression (MVD) surgery, also known as the Jannetta procedure, would have me very cautious before going under the knife.