It is possible that you have pulled a muscle in your chest. It really hurts and takes a while to heal. If you did some heavy lifting, or had a fall its more likely.  A heart attack may not show classic symptoms so if you go to the Doctors get them to do an EKG to check.  It could also be an infection or a digestion problem. 

 

You should call your work , and let them know you will be off work for a day or two, and are going to Doctors.

 

Let us know how it turns out.