Hi 'Midget', I guess they wanted to make sure that you weren't allergic to anything as this might mean you could have allergic rhinitis. And since you mentioned to them about the shortness of breath, they want to rule out things like 'allergic' asthma. In some way, it's good that they did tests to rule out stuffs instead of 'guessing' your diagnosis. But I'm sorry that you had to be poked so many times!
Vasomotor rhinitis is a poorly understood condition... what they know is that the lining inside the affected nose overreacts to anything that irritates it. Thus blood vessels enlarge and this results in chronic swelling and nasal obstruction. Irritants are stuffs like cold air, weather changes, hair sprays, air pollution..etc.
I was diagnosed with allergic rhinitis at first. After medications failed to help me... they thought that it wasn't really allergy but vasomotor rhinitis. The change of diagnosis made no difference to the treatment or my rhinitis status; medications still failed to help me and surgery was the only other solution left. After surgery, my right nose ain't too good but I can breathe better thru my left nose with only occasional small congestion.
Maybe you could suggest another blood test, RAST, like sneeydiva have mentioned to rule out allergies. Taking antihistamines might affect results sometimes. Good luck and hope the spray works!