Cough for almost 2 months now. saw 2 doctors for it about month ago - told lungs sound clear. had a chest xray & ct scan of chest (~2 wks ago)- came back clear w/ "perfect lungs". cough dry w/ very little clear mucus. taking mucinex dm - helps.

Many causes: Did you get a lung function test done also since cough-variant asthma may be the cause for your cough. Did you have a viral infection prior to the onset of the cough? If so, this cough may rarely linger on for up to 3 months. Nasal discharge from allergic rhinitis and/or sinusitis may cause a cough also. Consider seeing an allergist.