Hi docs, i do hv persistent cough day n nit with mucus when stressed. . x-ray chest n lung normal, hiv n tuberculosis negative. what cld be d prob?

Many causes : Sinus drainage is the most likely cause for your age. Allergies, exposure to toxins, airborne contaminants, certain chronic infections , smoking, and COPD are also possibilities . COPD is unlikely at your age. An allergist, pulmonary doctor or your primary care doc can help you sort it out

Could be allergy: What you are describing may well be a variant of allergy, with 'cough-variant asthma'. I would suggest a trial of over the counter allergy medicine such as Allegra, Claritin, or Zyrtec every night for 6 weeks, and over the counter Nasacort (triamcinolone) two puffs each nostril once daily for 6 weeks. If better, great. If not, see your regular doctor or an ENT specialist.