I'm 24 years and been a smoker for 4 years. I've quit smoking and it's been around a month. I had bad cough and generally would expel black mucus. It has reduced. I experience pain in my upper back whenever i breathe deeply,starting from spinal chord to ribs(right side). When i sit straight, this discomfort reduces tremendously. Got CBC report, in which my blood count is 4.4(normal 4.5-6) and ESR which is 16(normal 1-10).