1. New apartment building is toxic and killing me, slowly, on the left side.
  2. Mono.
  3. TMJ
  4. Silent GERD
  5. Open mouth night breathing causing recurrent tonsillitis.
  6. Glandular stones.
  7. Muscular something.
  8. Dental something.
  9. Picked up something in India in December.
  10. One of the vaccines for India causing this.
  11. Texting and phone holding, carpal tunnel running up neck into throat ...
  12. Chronic Fatigue Syndrome.
  13. Not cancer: had CT scan.
  14. Existential ennui
    Suggested by @evan