I've started having pain in my shoulder and arm the pain is at specific points rather than radiating, could that be a pancoast tumour?

Visit with your doct: A medical exam is required before we can figure out the cause of your pain. Pan coast tumor is a rare cause for pain in the shoulder/arm and the pain has a quality of being severe and radiation down the arms. Try mild pain medicine, if your pain does not improve in 1-2 weeks, you may need an X-ray of your chest to look for anything abnormal inside.

Your Peter Pancoast: 5% of lung cancers are pancoast tumors.The highest occurrence is in men between the ages of 40 and 60 with a history of smoking.The pain is often relentless and unremitting & adequate relief often requires strong pain meds.With time the pain can travel down the arm or even affect your eye & voice.If you fit this profile then see your doctor for a chest x-ray.If not, keep smoking til you get it.