Hi,
You need to stop smoking immediately - this is the most important thing considering your family history and
also past smoking history. Next - you need to get an appointment with a chest specialist at the earliest
possible. You would need blood tests, chest xray, if required CT scan of the chest to find out the cause of
your symptoms. This cannot be neglected as you have a family history of lung cancer and past history of
smoking. This could be a muscle pull or chest infection - but still no chances can be taken. Regards.