Many causes. Most commonly this will be from an infection such as a pneumonia but other problems including heart failure or other cardiac problems, bleeding disorders, blood clots in the lung, and cancer. This is a very serious problem that should be evaluated by a physician right away.
Many causes. Depends on age/risk factors such as smoking/environmental factors/exposure/immune status/blood clot/ etc. Very difficult to answer here. Could be something simple as bronchitis to unfortunately lung cancer. Need to be seen by md to establish a diagnosis. Need a simple cxr to a ct of chest.
Infection or Cancer. Coughing up blood is never normal. It can be caused by infections such as TB or pneumonia. It may also be a sign of lung cancer. There are many possible causes of coughing up blood and they all require prompt and appropriate treatment. Seeing a lung specialist as soon as possible is very appropriate.
There are several! Pneumonia, tb, chronic asthma, bronchitis all could cause your symptoms. Do you smoke? Coughing up blood is a serious problem. See your doctor, get a chest x-ray or even a ct scan to check it out!