Electric Shock Like Sensations In Chest That Eases With Advil, Persistent Soreness. Help?

I have electric shock sensations that begin in my left chest area (right above left nipple of breast ). In an instant, it travels down to my left forearms. I have had this pain in the past when my back was sore from driving a lot, but it would last for a second and leave. Most recently, I have had it several times a day and it lasts for up to 10-30 seconds which doesn t seem like a long time, but it is when you feel as though you are being shocked. It normally seems to happen when I am sitting. I am not short of breath, nor do I feel tightness in my chest. I took Advil yesterday and it seemed to help a bit with the sorness that remains in my arms and chest after the shock. I have recently recovered from Mono, and 7 years ago I had lymes disease. I am 50 years old (female). Thank you.