I have had a cold for six days, starting with a sore throat and then nasal congestion and now chest congestion and a severe cough. I initially took over the counter Dayquil and Nyquil for four days. Started feeling better yesterday, but by evening the cough and soreness in my chest began. Bought the generic Delsym cough syrup and using cough drops. I started this morning with low back pain -- wondering if that could be a symptom of my cold?