Hello, I'm a 19 almost 20 year old male and for the past 7-8 months, started about mid/late June 09, I've been having what I believe as heart pain. It always starts in the lower part of my heart feeling like I'm being stabbed then it radiates out to my center chest proceeding to make it feel like a metal steak was stabbed through the middle of my body and spine and I cannot move. As it starts to go away it moves all down into my left rib cage and hurts to breathe at that point. This has happened about 15 times in these 7-8 months. Tonight, however, it happened again making it number 16, but this time it started because of this cough I have. Like a congested, mucous cough, which started making what feels like my spleen or that area in the front and side hurt. Once I stopped coughing that area stopped hurting but then immideatley my heart started to hurt as mentioned above. During this time I could not breathe but my spleen area would start to hurt again making me cough. My grandmother died from a heart attack because of heart disease and I was a pre-mature birth when I was born with non-fully developed lungs. What could be causing all of this to happen? Are these minor heart attacks? How soon should I go to the doctor? (I'm fearing it for some reason)

Thanks

Additional info:
The heart/chest pain last for about a minute or two, but it feels like an hour goes by when it hurts.
When I say I can't move, it feels like I'm paralyzed from head to toe and only able to breathe and feel the pain in my chest
I've smoked cigarettes for about 8 years now, smoking a pack a day for about the past 2 years.