i have a sinus condition that settled in my Eustachian tubes and always post nasal drip.the sinuses in my cheeks are painful.i had used doxycycline a while back that seemed to knock it out.with a sinus infection decongestants and expectorants do not get rid of it.i have a doctor down the street but I don t think he likes to prescribe antibiotics.i was thinking about going to a hospital outclinic to get the prescription.so to sum up 1.is it possible with just decongestants and expectorants to clear a sinus infection of the Eustachian tubes that is stopping my head up and causing post nasal drip always and chest congestion 2.should I go to the outclinic to get doxycycline.