On 23rd August, I suddenly got a lungs pain and cough. I was a smoker, and I quit smoking recently. Since then, the lungs pain comes and goes, but it's better than before. The cough is also there, but it reduced. Any reason why it happened? And if I should get tests like CT Scan of Chest region and Sputum test or not? I started running and exercising on a daily basis since last month. I feel better, but still I just want to make sure everything is fine.