I've been dealing with a cough for about 20-25 days, sometimes it's wet, sometimes dry. I even caught a cold twice during this time. Initially, it was just a mucusy cough, but now I've got this mild pain in my chest, mostly on the left side but sometimes on the right too, and my chest feels heavy a lot. The mucus changes color, sometimes dark and thick, other times light and yellowish, but no blood. Most of the cold symptoms are gone now and the mucus has lessened. I smoked for about four years, around 3 to 4 cigarettes a day, but havent smoked in over two months since things got worse. There's no family history of similar issues, and I haven't had a fever. Could this just be a chest infection or is it something more serious? Please let me know what you think.