For 2 days have had pain under breastbone, and yesterday pain the back. now chest hurts like pluerisy. i am coughing a little, but no running fever.

Need a checkup: Pleuritic pain means it hurts each time you take a breath. While viral diseases can produce the symptoms that you have, bacterial diseases can do so as well. A checkup by your doctor and a chest x-ray should clarify things.

See a doctor: This could be any number of things, from infection (like pneumonia or bronchitis), to a spontaneous lung collapse (pneumothorax), to a pulled muscle or inflammation of the ribs. You should get checked out if it is going on for more than a couple of days.