Sneezing, itchy+runny nose even can't breath. Lung function test abnormal, not asthma. Blood oxygen 100.Doctor suspects hyperventilation. Caused by allergy?

Lung function? We need to know what is abnormal about the lung function to give you a better answer. Also, a single lung function test especially at a time when you don't have symptoms does not ruled out asthma. Do you have problem getting air in or getting air out? Does your heart rate go up when you have breathing problem?
Not enough info. Sneezing, itchy and runny nose are signs of allergic rhinitis. We can get a lot of information from a lung function test but we need to see it. If you have allergic rhinitis, your risk of having asthma is higher. In the info you provide, it looks like you also have blood work ups including immunocap or allergy testing. If the labs show elevated ige's, all of your symptoms might be allergy-related.