I agree you should see a doctor and at least get an EKG. You may want to go to the ER if the pain is bad. If you can get into your GP today that would be good. Often they will take you in if you tell them your symptoms.
mkh9
Better see a cardiologist - better to be safe than sorry. - A heart attack can hurt on the right side also - not necessarily always on the left. Hope you are okay