Having intermittent feeling of a sharp pain in the center of my chest. what could be causing this?

This sounds like it could be a chest wall issue. There is cartilage in the chest wall that can get inflamed, there are muscles that can get strained/pulled with activity, there are bones that can get bruised. Your doctor can examine you and likely determine which one you have based on physical exam and perhaps an x-ray. This is probably the diagnosis as long as a cardiac issue is ruled out.