Had a dry cough for bout a week. not cold or allergy. post nasal drip & cough worse in am. could it be from sleeping w/fans in room or ac @work?

Inflamed airways: Both upper, nasal passages/sinuses, and lower, bronchi, giving you these symptoms. Need to see your doctor / allergist, yes you can have allergies manifesting this way. Meanwhile, use saline nasal washes. Fans in the room /AC @ work won't cause it, but just trigger the symptoms. Check aaaai.org or acaai.org for an allergist in your area, best wishes