Good day, is it possible that my left back pain can be lung cancer, because i experience difficulty in breathing sometimes and easily get tired thanks?

Non specific sxs: there are many conditions can give you the same presentation like you described. - for instance, bronchial asthma, anxiety, plus minus anemia, muskuloskeletal problem, pleurisy etc. although it is possible, you are a bit too young for lung cancer. other conditions are more common . you should see your MD to get checked. some imaging like CXR or CT lung can show if there is mass in the lung etc.