I Had A URI 3 Weeks Ago Which Cleared Except

I had a URI 3 weeks ago which cleared except for dry cough with minimal clear sputum which is constant except when i take Benadryl at night along with mucinex. I've been using an Afrin inhaler and flunase inhaler. I have developed 1 flight doe over last two week. CXR is clear, nl heart size no clinical signs of CHF and no chest pain. What should I do. Albuterol inhaler doesn't seem to help. I started Singulair 1 day ago