I Had An Endoscopy Procedure Done 5 Wks Ago. I

I had an endoscopy procedure done 5 wks ago. I have had a tickle in my throat/chest causing a cough almost immediately after and it seems to be getting worse as time goes on. I went back to my gastro dr last week and he did not serm real concerned...told me to buy a humidifier and drink tea twice a day. He offered an antibiotic but i was uninterested...
Im wondering what it might be and what type of dr should i see?