How would you know if you had lung cancer, or what are the symptoms?

Usuall none: Until it's too late for a cure. Weight loss and coughing up blood are the two most familiar presentations, but lung cancer can do almost anything. Most often curable lung cancer is spotted on a chest x-ray. If you are 31 years old, you're younger than the vast majority of lung cancer patients. If you need help with smoking cessation, your physician has a variety of methods to help. Good luck.

New cough: Most cases of lung cancer are found by accident when a radiologic study is ordered for another reason. Symptoms usually indicate more advanced disease and could include weight loss, coughing blood, new cough, chest pain, shortness of breath.

Varies: As others have said, lung cancer is often silent until late. However, there is screening for appropriate candidates to help find it early. The following link may help: http://www.Cancer.Net/cancer-types/lung-cancer/symptoms-and-signs.