Coughing for 3 weeks.at first the cough was only a problem at night. now is a continuous unproductive cough due to an itchy throat. should i see a doc?

Yes: There are multiple causes for persistent cough. Could be bronchitis, acid reflux or post nasal drip among others. Treatment depends on proper diagnosis.

Yes....: Any cough present for 3 weeks or longer needs to be evaluated by a physician. Treatment depends on the etiology of the cough and this can only be diagnosed by a doctor. Possible etiologies include gerd and post-nasal drip (especially if worse in supine position) as well as bronchospasm or even a combination of these diagnoses. Treatment depends on etiology so see your doctor.