Is smoking causing my tight chest?

Hi, im 18 and recently started Uni. Since starting uni I’ve been smoking more then I normally do…im not a regular smoker at home - just occasionally - and I can stil go days weeks months without a ciggerette if I choose to and havent been smoking everyday at uni, just more then I would normally. anyway… I went for a jog today around the block where I live, it wasnt very far but I dont run often - like hardly ever - I felt O.K when I was running but when I got in I couldnt catch my breath and had a horrible cough which hurt my chest badly - my cest was tight and when breathing in deeply I would weeze and get the cough. Its gone now - 5 hours after - but I still have a slight pain in my chest. I suffer from an eating disorder as well which I am recieving treatment for, but I dont think its got much to do with that at all, for many reasons I cant explain now but.. could it be the smoking which has caused this pain? I’ve been running before and really made my self exhausted from it, but never had this happen, and I wasnt even that tierd after. Im not going to smoke anymore and see if that helps, as I really want to run more and I know that smoking will gradually effect my fitness levels… im just wondering if this is anything to worry about? - I dont have any history of asthma at all, and never experienced anything like this before.. Any advise would be great… thanks Lilian