Dear friend, welcome to HCM!
Ideally an answer without seeing the Xray is not possible.
You can upload the image using the uploader on this website near the text box.
From your description, it appears to be some lung infection
with pleuritic pain, which reduced with antibiotics.
Could you post the details of the antibiotics?
can predispose to lung disorders, infections and cancer and cause Xray abnormalities.
So quit permanently.
The decision about a CT scan
will depend on the Xray findings.
Take care and please keep me informed of your progress.
I hope to have answered your query satisfactorily.