Any problem in breathing? What is your blood pressure? Do you have nausea? Since how long you have this pain? Age and sex? Any other symptoms?
Pain in left side of chest, should always be checked for cardiac origin, So firstly get an EKG done.However It seems a mascular pain.This condition is called as Costochondritis.It is an inflammation of the cartilage joining ribs to chest bone. It is this inflammation that causes the sharp chest pains inside the chest wall.Other reason can be pull in the muscles or ligaments of ribs..
So a proper physical examination is must along with EKG ,along with Chest X-Ray. See your Physician, for further follow up.
You can take Motrin ,and your doctor can prescribe anti-inflammatory drugs. get a checkup from your doctor.