Suspection of Lung Cancer.

I am writing on behalf of my beloved gf.
About 10 months ago, for the purpose of job(air hostess), she has to do her chesr x-ray. Which showed some patches on her lower left lung.(uneven sized pathces). She had a sever cold and cough before all this, which went away ina a week. She showed to a general physician, and he bluntly told her weather it is tb, pneumonia or even a cancer. She has worked as a RN too, she thought it wasn't a cancer. So she took antibioic that was prescribed by the samme doctor, And repeated xray every week, after 3 months patches started decreasing. I don't know if it was pschycological, but she kept on telling me that she has short breathness and she has also lost some weight over the time.
Now she came back home for a month leave and wanted to do a entire body check up. She had few problems like, gastric, lower back(tail bone) pain and stuff. She happen to do the xray again. This time the exact same pattern is on the right side and the LEFT SIDE HAS GONE AWAY. THe fact she has been going out in cold a lot, has caused her coughing and cold again too. She showed it to a radiologist and he said it is an infection. But this chest doctor told her to do the biopsy. She cant do that right now coz she has to go back to her work. And she has procrastinated that for april, her anothere leave.

I am really worried if she all these are symptoms of cancer. I mean where is she heading. She is just 23 and has never ever smoked.
Please help me out on this.