What Causes Coughing Up Phlegm From Chest After Sleeping?

Question : Since late 2/2015 have had allergies, maybe from the office, dust, dry heat or we are having a drought, hardly any rain, very dry weather. Had took Allegra for about 3 weeks, to help with nasal congestion, sneezing, swollen eyelids. When I go home symptoms improve. Continued with allergies, about 2 weeks ago had a very bad cold, tired, thick clear mucus from nose, stayed home a day or two, got better. Currently, the last two days, I guess I have had a sinus infection all along, now have thick yellow mucus discharge from nasal, and also now chest. Only cough up phlegm from chest after sleeping, and a small amount during daytime, no fever, a little tired but don't really feel sick. Lost sense of taste, I can breathe easily but have congestion in sinus cavities. Also, have a very dry, hot, nagging cough, that does not produce phlegm, almost feels like I can cough myself into laryngitis. At night, can't sleep because of dry cough, took left over medicine doctor gave me from 2013 - Iophen C NR liquid (when had same thing, but running out of cough medication). The mucus has gotten more yellow and thicker since last two days, seems to be progressing. Taking Safeway Care Non-Drowsy Muli-Symtom Cold Relief CF for cough suppressant, expectorant and nasal decongestant. No known allergies, but will get retested next week.