Sinuses are air filled cavities around nose. Any inflammation of nose can lead to inflammation of sinuses and this can be due to allergy, infection or a combination of both. In allergic rhinitis one has frequent sneezing, watery/ whitish/ yellowish nasal discharge and nasal blockage. In infection patients have dirty thick greenish discharge with sinus pain and blockage. Headache is caused by collection of secretions in the sinuses due to blockage of the drainage sites of sinuses due to inflammation. Treatment is started on clinical grounds. Sinusitis needs long term medical treatment as blood supply of sinuses is poor. In refractory cases CT scan helps in knowing the exact extent of the disease. You need to see an ENT doctor for assessment and management of your sinus problem.