Naproxen for chest pain?

I have been having chest pain and was given a chest x ray and e.k.g. and was told my heart is fine I was prescribed naproxen 500mg pills and they work but when I'm off them my chest pain is back. I don't no what to do I can't take naproxen forever. Does anyone no what's wrong with my chest or a safer treatment or remedy? How long can o take naproxen before it becomes dangerous for my liver? Thanks for Any of your answers?