I have upper back pain, chest pain and pain at top of left arm, i smoked for 20 yr, quit 5 weeks ago, could i have lung cancer?

Back and chest pain: Honestly there are many things that you could have including cancer or heart problems . But i would first recommend that you see your primary care physician as soon as possible for evaluation.

multiple causes: Your symptoms could be due to anything, simple muscular to heart disease. Try simple conservative treatment with over the counter pain relievers for a couple of weeks before going to the doctor.