According to the data you provided, it seems possible that you might be experiencing pulmonary edema due to heart failure. Since the heart does not have sufficient strength to pump, a certain quantity of the blood stays in the lungs. Part of the blood (plasma) might even pass through the alveolar walls and fill the lungs with fluid thus decreasing the active surface for respiration and making the breathing more difficult. The fluid puts pressure on the respiratory mucosa thus hurting it and even causing minor bleeding in more severe cases. Many patients experience difficulty breathing even when sleeping. So they are advised to sleep with more pillows thus enabling the gravity to help in draining the lungs.


However, lung cancer can not be ruled out solely on the data you provided and further examinations (physical examination, X-ray or CT-scan) have to be made in order to rule out lung cancer.