I have had nausea, sometimes vomiting, dizziness, neck pain for two years. Have been to ear, nose and throat specialists, neurologist, therapists . I have not been diagnosed with vertigo . The only illness I have ever had was shingles . I have now been in touch with the Mayo Clinic hoping they can diagnose what s wrong. I am 78 and worked until I was 75 and have always been in good health. Can you suggest a cause