Sinus Medication Solution

I have had one for 7 years now , I have been treated by G.Ps. and by an E.N.T. specialist. . I have had repeated long doses of antibiotics lke amoxycillin but no avail.I have also had a scan of my paranasal sinuses. Doctors I have seen since have told they are not willing to prescribe anything becasue although the infection makes ny breath smell , it is not caused by pathogens.