What Does Shocks In Fingers Radiating To Arm And Chest Mean?

Hello, I've been getting these shocks that start at my finger tips and run up my left arm straight to my chest. It is only for an instant but the pain lasts for hours and sometimes the whole day. After I recently gave birth, the shocks happen more frequent and the shocks get more intense. I was wondering what I should do and if possible what is this "shock" feeling called.