please bear in mind that sinuses are openings in the skull, some r connected to the nasal passages.
sinusitis, that is inflammation of the sinuses can be due to infection or allergy. when this happens, the membranes lining the sinuses secrete a fluid which comes in the nasal passages, plus the lining of nasal passages themselves secrete fluid which adds to the "runny nose"
when the sinuses are involved, u have headaches and discomfort the facial region.
the best treatment is steaming ur face regularly (if it happens in winter), in summer u have to determine the cause first:
allergic- runny nose, itchy eyes, cough, usually related to high pollen count, dust or can also be food related. it is treated by anti hisamines (loratadine 10mg), paracetamol for any pain or feverish feeling ( always take it after eating something, never on an empty stomach)
infection- it can be viral or bacterial. these days viral infection is quite common. viral infection is treated by taking paracetamol, gargling regularly with warm salt water.
if this problem is persistent, then u most probably have chronic sinusitis. and for that i would suggest u consult an ENT (ear,nose, throat) specialist who will examine ur nasal passages and might even do an x ray of ur sinuses if he finds them to be the cause of ur discomfort.
for nasal obstruction, xynosine spray is good, as mentioned before but it can be quite discomforting itself. steam, or hot drinks (such as green tea, the therapeutic benefits of which have just been mentioned) are very good and also yakhnee( chicken stock broth). the steam basically liquifies the crusts or blockages that form in ur nasal passages. plus take anti histamines, but take medicines when the aforementioned methods do not work.
please note that u should always try home remedies first, as a doctor myself i believe that most problems such as this can be cured by that. but if the problem persists, u must take medication from a specialised doctor.