Hello. I'm Dr. Christensen.
I'm sorry you're not feeling well. Your cough, congestion and discomfort could certainly be linked to your
lung cancer treatment:
lung surgery can alter the architecture of your airways and make you more susceptible to respiratory infections. (Patients who undergo radiation therapy are particularly prone to post-treatment infections.)
However, people who have any kind of pulmonary condition -- asthma, emphysema,
cystic fibrosis, etc. -- are more susceptible to infections, too. Your current symptoms are more likely due to your underlying
pulmonary compromise, rather than your past history of cancer. Given your history, I'd suggest you call your physician for advice. He/she may want to examine you and get you started on an antibiotic. (Although most respiratory infections are caused by viruses -- which don't respond to antibiotics -- people with underlying lung problems tend to develop
bacterial pneumonia more easily, so your doctor may want to be proactive in your case.)
I hope that answers your question, and I hope you feel better soon.