The colored mucus means that you got a sinusitis (It was one of etc in my post ).

Sinusitis cause running in the back of the nose (post nasal drip) that infects the larynx and/or the pharynx. Your other symptons are compatible with a sinusitis, also.

With a mild allergy, you don't get sore throat or headaches, otherwise, if the allergy causes a sinusitis, you have the symptons you describe.