I am having pain under my left armpit, left arm and left side of my back. is this a sign of a heart attack should i go to the emergency room. i am a 38 year old female?

See below: You don't give enough information about your CV risk or character of the pain to to make an educated guess - as a 38 year old woman , chances are it is not cardiac - on the other hand, woman can have aypical symptoms with cardiac disease, and with certain risks woman you age can have heart disease -I would see a doctor about this - either in the ER or with your regular doctor