Any history of sneezing and something dripping at the back of your throat? Color and consistency of the phlegm?
You may be suffering from allergic rhinitis (for which you need antiallergic meds) or sinusitis (which may require antibiotics)
Based on the limited history it is difficult to advise treatment.
Next Steps
Please visit an Ent specialist for diagnosis and further management.
Health Tips
Steam inhalation, saline gargles, plenty of fluids