question: Hi, I have a sharp pain in my chest in my back when I wake up... it's usually behind my left lung and easy to pinpoint. I am a smoker, but only smoke 8 cigarettes a day at most. I don't use drugs. I am 18 years old, 5 feet and zero inches tall, and I weigh 104 pounds. I have a history of mild costochondritis. Is my smoking related to this sharp pain?