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.