What Causes Fluttering And Spasms In The Chest?

Hello,

I have been looking on the internet for a couple years for an answer but have not yet found one. I am a 40 year old male who has developed fluttering, spasms, twitching specifically in one area: the left side of the chest, right by the nipple. I have it about 3 times a week. It started about 6 or 7 years ago and has become progressively more intense. I have visited doctors and have done research about it and have tried many different treatments and none so far have had any long-lasting effect. Doctors have told me that it is anxiety and that caffeine and smoking can exacerbate the symptoms but cutting down on smoking has not improved my condition and I don't consume beverages with caffeine. I have tried magnesium which is supposed to calm the nervous system but have not noticed any difference. The only correlation I can come up with is with sleep. It seems that if I sleep poorly in the night, chances are the twitching will start with accompanying heaviness during the day. The only causes I can think of at the time when it started were being very overweight and exercising constantly which led to a quick loss of 60 lbs. I also had a tooth infection at the time which I didn't treat and subsequently became abscessed. And lastly I had received 1 session of ECT therapy for depression about 11 years ago, after which I did feel strange numb sensations. Any help would me much appreciated.