chronic nasal obstruction

i am38yrs old suffering from chronic nasal obstruction since childhood only gets relief by xylometazolin nasal drops.I have shown to many ENT specialist,gen.surgeon,internal medicine & allergy specialist treated with systemic & local steroids, systemic & local antihistaminics,antiseptic gargling ,lukewarm water gargling but of no use...& also treated with tonsillectomy & nasal septoplasty in childhood without any effect.My maternal uncle & my 4 yrs old daughter also suffering from same problem.
               Now  i m suffering from chronic granular pharyngitis & also wheezing (brochits) requires occasional bronchodilator only at the time of acute bronchitis. i have no H/o allergy. Wheezing gets only at pharyngeal level..chest auscultation remains normal.
                So what is the cause of my (?Hereditary) nasal obstruction? what is medical & surgical treatment for nasal obstruction to get cure? & how to increase tone of my pharyngeal muscle & soft palate (as it is decreased by chronic inflammation)  ..