I have severe nose pain in my upper left nose. saw ent years ago w/ cat scan which was negativ e. please help?

Consider neuralgia: This pain might be a neuralgia, most likely of the trigeminal nerve. Usually this pain is triggered by touching certain points or breathing in and is brief and stabbing. It may appear for a time then resolve only to recur. There is an atypical form where the pain is constant but is still intensified by touch, breathing, cold air blowing on it. Suggest neurologist.