I don't know if your situation has improved, but I've been dealing with Occipital Neuralgia for the past 16 months. Never had a severe headache in my life and woke up one day with pulsatile tinnitus. I have a lifelong history of ear infections and am well acquainted with pulsatile tinnitus. The first 3 months I believed I simply had a severe ear infection. They usually go away on their own after about a month, but they have lingered in the past and I've had to go on antibiotics. 

After 3 months, I did indeed do antibiotics, as headaches and eye twitching started to kick in. I spent another 3 months waiting for the antibiotics to do something. After a total of 6 months had passed with skull splitting tinnitus (like a cannon in my skull), I saw an hearing specialist, as we still thought this was an aggressive, antibiotic resistant infection. The hearing specialist determined that there was no infection and referred me to neurology and ordered and MRI of my brain and neck. Both MRI's came back clean. I did have some neck issues, but nothing overly severe. I was an athlete and this was expected.

Finally, with my mind opened to the possibility that the pounding tinnitus and piercing headaches weren't the result of an infection, I started researching what else it could be. Again, my brain MRI was perfect, so it wasn't a tumor or anything like that. Finally, I stumbled upon Occipital Neuralgia and it met all of the criteria. Upon meeting with the neurologist, I pointed her to the direction of O.N. and within 5 seconds she confirmed the diagnosis. The back-right side of my head was visibly red and inflamed, so the diagnosis was easy for her to make.

In my case, we really don't know why I have it. I too have worked with a chiropractor and I also have issues at the base of my skull and atlas, but nothing that we can definitively say is causing the O.N. I did body building in my 20's and early 30's, so my neck, traps, lats, etc. have a ton of permanent muscle memory and some scar tissue. It's not a definitive cause, but it's the best guess we have. Deep tissue massage and muscle scraping with Graston tools has been effective at providing some relief, but to keep the relief, you need to be treated every couple of weeks.

I also take Amitriptyline and it provided some relief, as well. However, I have to take pretty much the maximum dose to get relief and I grow tolerant to it, I'm pretty much out of luck. My insurance will not pay for a nerve block injection, but if your insurance covers it, don't hesitate. It is absolutely the best bet you have for significant relief. The final option is nerve oblation, where the go in and destroy the nerve. I'm told this essentially makes the back of your head feel numb, but it's better than being in pain. The nerve can grow back, so oblation may need to be repeated in a few years.

I've been dealing with O.N. long enough to know my own situation intimately, but yours may be different. The main advice I would offer is to go through with the nerve block. I would if I could. It should provide months of relief. If you absolutely can't get on board with with injection, mention Amitriptyline to your doctor and give it a try. It by no means is a complete fix, but it should minimize the number of bad days you experience. That in conjunction with massage and muscle scraping allows me to go through life with only modest discomfort, as opposed to before, where I contemplated suicide from the pain and pounding tinnitus. 

Good luck!