I have gone through something similar. I still have daily headaches (but not as intense). I have had MRI's, CAT scans, and gone to every type of doctor imaginable. I did determine finally about 1 1/2 years ago that I have TMJ. You don't have to have your jaw lock up on you, or have it click or pop all the time to have it. It can be that your bite is offset (especially if you a clencher or a grinder). Anyway, I found a doctor in my area that specializes in TMJ. I got a splint (that I wear all the time with the exception of when I eat) that evens out my bite. At first my headaches got worse, but that was because there was a foreign object in my mouth and I kept biting down on it (or rather clenching on it). Once I got used to it they eased up some. Before my ears would ring, I thought there was always something wrong with my sinuses, my ears would clog up, I would get dizzy, pain behind my eyes, my temples were sore, my teeth hurt, my neck, etc. Anyway, if you look up TMJ or TMJD and look up the symptoms, you may find that you have this. You certainly sound like you have some of the typical symptoms. Hope this helps.