It would be highly unusual but not unheard of for a woman your age to have heart disease, or a heart attack. When you say it happens every now and then, does that mean you've seen a doctor about it? If not please do!
A couple things can mimic cardiac pain.
Gall Bladder pain is often mistaken for cardiac pain ... and the fact that you mention the referred pain to your back makes it sound even more like GB pain. It's generally a disease of older people, but it's certainly a woman's disease (primarily). Often, but not always, you get some nausea and vomiting with GB disease.
Severe indigestion can be amazingly like cardiac pain. It's in just the right place, it can be heavy and it'll refer ... sometimes to your neck or back.
Take some kind of antacid. If you have alka-seltzer, take that. It contains something for your headache, too. If not take tums, rolaids, mylanta, etc. Give it 20+ minutes to work. If your pain is resolved it is probably indigestion. You still need to let your doctor know about it!!
If you're really scared, go to an emergency room. And just an fyi ... the internet chat area may not be the best place to be getting advice about medical conditions!
I worked as a nurse for about a zillion years. I also had gb disease!