How To Cure Muscle Spasms In Left Breast Area?

I am going mad! I am experiencing what feels like a pin prick pain and sometimes muscle spasm above the left breast area. I panic about this and then I feel worse with a bit of tightening in the throat/chest. I have had a 7 day holter and even monitor that was reported as normal. I do have some acidity. I just want to get over this and feel well but I am terrified about my heart - what should I do next.