30 yr old 8pack year ex smoker. No cough, no shortness of breath or wheezing, slight pain on side of chest and sometimes in chest. Scared of cancer?

You should be. Scared. Smokers have a greater risk of cancer. You need to see your doctor to be evaluated. Hope this helps.
Visit your doc. You are young and smoked for a short period of time (congrats for stopping, by the way) so odds of cancer are not too high. Still, i would advise you see your family doctor for an evaluation and most importantly, do not fall in the smoking habit again. Best to you.