I don't have a fever, swollen lymph nodes, headache or rash. just have a mild sore throat with nasal drip. take a cough drop and it disappears for a while but comes back later. any idea?

Possibly allergy??: You may well have an allergy manifesting itself by having you generate mucus in your nose. It can then exit your body through your nostrils or by sliding backwards go down your throat. That might cause you a sore throat, coughing, and a sense of having to clear your throat frequently. You can treat yourself with allergy meds or find out what you're allergic to and avoid it!

Viral: Most likely a viral upper respiratory infection. Could take a cold Sudafed for symptom relief for a couple of days. If symptoms worsen or new symptoms appear, seek professional counsel.