I have some mucus in my throat and can't seem to cough it up, is this cancer or emphysema?

Hopefully neither.: More likely post nasal drip or gerd.Do you smoke?This is a very common cause of mucus in the throat.Allergies are another.Cancer of the throat is most often a silent disease-more seen than felt-until late.Emphysema is a breathing disease-you can't catch your breath after minimal exercise.At any rate you should see your dr and get a dx.

Chronic bronchitis: Do you smoke? If you do this is likely chronic bronchitis which is a direct consequence of smoking. Emphysema causes breathlessness, but not sputum production. Cancer of the head and neck can cause a feeling of mucus in your throat and so can lung cancer. You should be evaluated by your health care provider for these symptoms.

See doctor...: You need to be seen and examined by a doctor for your symptoms to be diagnosed and treated. You may even need some tests done to determine the difference. For example, you may need a chest x-ray and pulmonary function testing. If you are smoking, smoking cessation is a necessary part of treatment and your doctor can help with this as well. See your doctor asap!