You seem to be suffering from an allergy which could be the maintaining cause recurrent bouts of nasal blocking, nasal discharge, discharge falling back into the throat leading to regular bouts of throat irritation, infection, cough etc. This discharge over a period of time gets clogged in the empty spaces of the skull called sinuses causing sinusitis which as time progresses becomes the source of infection. Homoeopathic medicine has good remedies like Calc carb, Kali bich, Corallium rubrum etc. to see that the bout of cold subsides and also help in relieving the sinusitis.