Spot on my xray

[preop]

I recently took a full pulmonary function test for a pre op evaluation all my information was good on this test for my breathing however the chest xray showed a spot on the left lung.  I had a previous xray in march it was clear and also in July when I had a car accident and had chest pain immediately following the accident.  I have no duress or immediate symptoms several weeks ago I had a real bad cough but it has gone away almost.  My doctor will not clear me for the surgery till this spot is gone and is only taking xrays to determine what it is and on the second xray it seemed more than what the first xray stated in the report.  I need this surgery what can I do about this as I also don't want to risk my life either.  I want a second opinion.  At first the Pulmonary doctor said it might be a slight colapse of the lung now she is saying it may be some infection I think she speculates too much what can I do to pin point this?