Hi,
Welcome to HCM,
You are suffering from VMR (Vaso motor Rhinitis), nasal blockage is non allergic in case of VMR and many times it is along with blood defects like high Eosinophil count. There could be any structural problem or Sinusitis?Any Infection or tumour needs investigations.
It would be Appropriate to consult a ENT Surgeon anf after examination a investigation may be a X ray PNS or CT Scan may be performed depending on your investigations and physical examination a treatment can be advised to you to give relief as far as possible.
Best of Luck to you.

Hi welcome to Health care magic forum. Chronic nasal obstruction since 2years, suuggest sinusitis, probably with D.N.S a septal defect or allergy to some substances you are regularly using in the night like spray, deodorent, bed clothes, night dress etc. I advise you to consult an ENT surgeon for diagnosis and treat ment.
besides i advise you to follow some non medical recomendations. You will be the correct person to find the allergens you are sensitive. You observe the things after using them you get more of nasal obstruction. On taking what foods there is more nasal obstruction. On repetition you try to avoid them.
Diet recomendations as, avoid taking brinjal, fish, other sea foods, fruits and juices, as these tend to increase the allergy. take more of green leafy vegetables pulses, sprouts, milk, egg, meat, and dry fruits to build up blood and resistance. Wishing for a quick recovery, and thanks for calling.