I'm 39 & quit smoking 7 years ago. had some blood in phlegm & doctor gave me z pack (blood gone). chest x-ray clear but upper back pain. scared!

CT of chest: If you are at high risk, a ct of your chest would be more definitive. At your age, though, I am not sure that your risk would be that high. Consult your doc.

Possible: Stop smoking forever get over the cold and bronchitis, and any pleurisy good about the xray get the back checked for back issues, unlikely lung related. If not improved in a couple of weeks consider ct scan.