28 yo frequent sinusitis sufferer. Headache, cough, fluid behind ears, tickling in throat. Reoccurring sinus infection?

Need to examine. It is not feasible to provide a meaningful opinion without taking additional history, physical examination and may be some tests. It would be prudent to see an ENT doctor. There may be underlying issues, e.g., a deviated septum, or immune deficiency that would require an evaluation. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Drink enough water daily so that your urine is mostly colorless. Practice safe sex.