It happened to me. I also went to a pulmonologist who gave me medication then went for x-ray again in a private hospital. Result was negative then went to another medical clinic for agency medical exam which I passed. Now I am working after medical exam here in Doha with x-ray result that was also negative for lung scar. The pulmonologist told me that it could be that the plates used on the first x-ray was old and defective. It is always best to seek second or third opinions.