Since your history says that you are having recurrent Respiratory tract
infections, we here list out some of the common causes. 1) Allergy 2) Tuberculosis
3) Smoking and passive smoking
(in the environment of smokers 4) Decreased Immunity be it Congenital or Acquired 5) Local anatomic defects like DNS, Tonsillitis, Sinusitis. 6) Cystic fibrosis
. The management differs by each cause hence see an ENT specialist
or a General Physician to figure out the cause for you. The appropriate treatment is instituted automatically by them. Remember to avoid smoking, try to reach your office during low rush hours, Healthy diet at home (Outside food should be minimised). Breathe fresh air early in the morning with a 20 min walk. Dont stay in congested surroundings. Water should be properly boiled and then cooled before drinking.