Random racing heart

For the past week or so, I have been noticing problems around in my heart area.

First, I began getting what I thought was acne on my back. A large patch on my back, a bunch of little bumps that are very red. These were located in the general area of where my heart would be. A few days later, a smaller patch appeared on my chest, again in the area of my heart. This could be irrelevent, by its still suspicious of my situation.

Then, about two days ago, my back started to become a little sore and tense. Yesterday,I began to feel a little pressure in my chest, and then later that night I began to notice my heartbeating alot faster, and a little harder. If I stayed really still and quiet, I could feel and hear my heart beating quickly without putting my hand over my heart.

And now today, I began to feel not too painful sharp pains in the heart area, which only lasted for about 2 seconds at most. I found my heart racing during most of the day at school, and even when I tried to start to take a nap when I got home. Aftermy nap, my heart cooled off, but still began beating faster if I bent down to pick something up, etc.

I am 20 years old and going to school. I'm wondering if it has something to do with the fact I have been eating alot of fast food this year, probably 4 days a week I stop in for a burger or sub, due to a busy schoolyear and not having much time to cook.