Hello~I am sorry you are experiencing these symptoms, vertigo is awful.
Have you had any MRI's or Cat Scans on your neck, sometimes they will show up things that could be wrong? Have you had seen an ear specialist to rule out any inner ear disorder?
I would suggest, since you have tried other venues, that you try a chiropractor, you may have some misalignments in your neck or upper back, although, I would think that would cause constant issues, but still, the body is a complicated machine, so anything is possible. The chiropractor will take x-rays of your neck and back, study them, then go over the results. After a few treatments, if it is due to neck or back issues, you should start to feel better.