Female left pain, could it be cardiac?

Hi. i'm 31year old female. For the last 2 days i've had a pain that came on suddenly in my left . It comes and goes in waves, and feels like a dagger is being squeezed into that area. Around the nipple or just above. I never felt pain in that area as strong, although i have had previous small niggling pains in that over the last few months. About 6 months ago i had an ecg, heart echo, and stess test (on treadmill) done and everything was clear although i was found to have etopic beats but heart specialist said they were harmless. I only got these tests done because i was suffering from palpitations at the time, never pain....Do u think this pain is heart related. Are you likely to have pain in your like this from your heart??