@slw18 I read your symptoms and I think a physical therapist may be able to help. Find a PT who rehabs spine surgery patients. You are describing symptoms with muscle spasms that can be caused by misalignment of the spine or muscle spasms that cause the vertebrae to be pulled out of alignment. A good PT can be a great source of information and will likely know doctors who can help because they get referrals from doctors. Your imaging didn't indicate any brain tumor, and if there was an issue like that, they would have told you. It would say something on the report.

Mayo gets lots of patients trying to see neurologists and it is hard to get into Mayo for that. May I ask why you have been seeing a chiropractor for years and what has actually been diagnosed as a spine issue? If you do have a problem like a bulging disc, seeing a chiropractor can be dangerous. I am a spine patient and had a bulging disc resulting from an old whiplash injury, and all I had to do to rupture that disk was turn my head while I was stretching. That didn't hurt, but had an odd feeling. In the next few years, I grew bone spurs pressing into my spinal cord trying to stabilize that ruptured disc. It caused spinal cord compression, and I had to have surgery to remove that damaged disc and a fusion of the 2 vertebrae. I had the same symptoms you describe. The suboccipital headaches are caused by the vertebrae twisting or tilting from a muscle spasm. Those muscles are attached to the spineous processes on the vertebrae and to the base of the skull and they get stretched if pulled out of alignment causing pain.

My physical therapist is also has an expert level myofascial release certification from John Barnes who developed the treatment techniques. I would caution you against further chiropractic work if you have an un-diagnosed spine issue. That is a jolt to your spine to have an adjustment and the cumulative effect of that over years may not be good. A doctor would have to advise you about that. Discs develop cracks from trauma, and years later as the discs dry out with aging, the cracks weaken and can open causing the disc to herniate and spill out the jelly like substance inside. For me that happened 20 years after a traffic accident.

A physical therapist can gently work on the muscles to realign them and restore normal movement, and has modalities to treat pain and spasms with out blunt force to the spine. You skull may be sitting crooked on top of your spine. That sometimes happens to me, but I also have thoracic outlet syndrome that puts uneven pressure on my neck with one side being too tight, and that can cause independent rotation of vertebrae. If you have a spine issue, getting a referral to a spine surgeon would be a good idea. That doesn't mean that you would automatically need spine surgery, but would be evaluated. Sometimes, they only look for problems to fix, but they can send you to physical therapy to try to prevent surgery. They should want to prevent surgery unless it is necessary. At the very least, you need to do PT and have it fail to help before advancing to surgery.

I didn't wish for surgery, and I was scared. I had to do a lot to get over that. I was loosing the coordination of my arms which was serious since I am a professional artist. One piece of advice I would give you is let the professionals diagnose the problem. Don't tell them what tests to do and what you think the problem is. No one wants to be told how to do their job. Your job as a patient is to accurately describe your symptoms, when they started, what your health history is, and if your symptoms change with different positions of your neck or body or have changed over time. You can ask them to review your imaging with you. Try to be calm. If you are demonstrating anxiety, they may be put off by that or refer you for mental health help. Surgeons are nervous about the patients they select for surgery and want to insure the outcome will be favorable. Anxiety will get in the way of good communications and can interfere with a doctor patient relationship. Their understanding of the problems are based on communication and it is easy to get it wrong or miss something.

Do not put your doctor in the position of having to decide if the chiropractor caused the issues. Tell them your history and they can have an opinion on it if they choose, but they may leave that out of the records. If the doctor thinks they will be pulled into a malpractice lawsuit because of the chiropractor, they may not take you as a patient because that will put them in an awkward position that may be very time consuming. Often there is a question on intake forms about this. Surgeons pick and choose their patients carefully, so make sure you are the best patient you can be. Some fear is normal, but don't scare the doctor out of helping you. If you need counseling, find a counselor yourself who can help you navigate the issues.

Here is our discussion about Myofascial Release and there is a provider search at http://mfrtherapists.com/
My physical therapist has done a lot of this in treating my spine issues, rehabbing me after spine surgery and treating my thoracic outlet syndrome. Let me know if you have other questions, and I will try to help.
https://connect.mayoclinic.org/discussion/myofascial-release-therapy-mfr-for-treating-compression-and-pain/