Interesting comments that I feel require a reply. My suggestion re a mild case of vertigo is based upon the fact that three years of musculoskeletal therapy has failed to address your problem as well as your description of motion sickness etc. ENT exclusion of severe disease does not exclude what I am suggesting. I have been involved with tinnitus patients for many years and have written a patient study on the subject. I am also involved with musculoskeletal and sports treatments and treated head injured neurological patients for many years. Although I often speak with people and have friends in many professions I do not profess to have their qualifications or to give advice regarding their professions based upon occasional conversations.
There may well be other explanations for your symptoms, but in a search for relief it would be unwise to discard suggestions out of hand unless they are totally illogical.