Hello & thank you for Q on HCM Your symptoms are suggestive of start of throat infection ( possibly viral) which can cause throat pain. You must see a Dr for examination of throat, chest, ears etc to make sure it is viral & not bacterial (as for bacterial inf anti biotics are needed). Viral illness id self limiting & with time it will settle - take paracetamol, lot of warm to hot fluids & rest is what is needed. Smoking is a predisposing factor for development of throat (difficult swallowing, weight loss change in voice) Oral cancer causes non healing ulcer in mouth which can be painless also some times & also can lead to difficuty with speech & swallowing . Lung cancer is suspected if one has chronic cough with blood stained sputum, chest pain & shortness of breath. I hope this helps to alleviate your concerns but overall it will give you lot of health benefits if you are successful in stopping smoking.