My heart palpatations happen literally hundreds of times a day. Is this normal?

In Summer 2002 I went to the doctor because I had started feeling a 'sinking' feeling in my chest. At that time I didn't think it was my heart as it was more like when you take a breath in but have phlegm on your lungs. Anyway, the doctor said my heart could be doing an extra beat, everything sounded fine and I was probably stressed (I was in second year at universtiy).After that they seemed to go away for a while, then Autumn 2006 it flared up again and I went to the doctor where I now live. I was hooked up to a monitor for a couple of minutes, and they said the reading was a bit inconclusive but probably fine and I was probably stressed as I had just started a year's post grad degree. The symptoms have been there ever since, and I think the palpations are getting much more frequent. Also sometimes when it happens I then feel a kind of rushing sensation up to my head for a second. I've always been afraid to take my own pulse in case my heart is stopping beating, but today I did as the