Regarding your first question, lung cancer is most commonly asymptomatic in the early stages. More advanced stages of lung cancer can be associated with cough, bloody sputum, shortness of breath, pneumonia, weight loss, and decreased appetite, among other symptoms.
As I am not sure what is upsetting your stomach (or what these symptoms are, exactly), I'm afraid that I won't be able to answer this question.
"Ask a Doctor" questions are answered by certified physicians and other medical professionals.
For more information about experts participating in the "Ask a Doctor" Network, please visit our
medical experts page.
You may also visit our Lung Cancer , for moderated patient to patient support and information.
The information provided on eHealth Forum is designed to improve, not replace, the relationship between a patient and his/her own physician.
Personal consultation(s) with a qualified medical professional is the proper means for diagnosing any medical condition.