When you have lung cancer, you could get complications like blood clots or chest pain, especially as your disease gets more advanced. There are a number of ways to treat these problems and feel more comfortable. Lung cancer sometimes spreads to the airways that bring oxygen into your lungs, causing the airways to narrow or get blocked. When this happens, it's hard for your lungs to fully expand when you breathe in and may cause shortness of breath, called dyspnea.