felt really good after stopping smoking but after 3 weeks of feeling a lot better, I woke up 2 days ago feeling awful. I have a pain in my upper back, my chest feels tight, I feel really tired and I feel more breathless! What's happening? should I ho and see the doc on Monday or is it an exasibation! I have no idea what and when I should worry. I keep trying to read about copd but it's very confusing and worrying!!!