Normal chest x-ray .. having persistent cough for 2 months that sometimes gets better and low grade fever that comes and goes?

Respiratory infect: You have an inflammation in your upper respiratory tract which is probably due to infection. Would need far more info to even begin to speculate, particularly since do not know what you mean by a low grade fever. One of the more common causes would be Mycoplasma or adult pertussis. If you want to provide more info rephrase the question.