Arrgghh! What's wrong with me?
 

Within the last few days, I've been having this twitching or fluttering in my right upper abdomen/lower chest. And, now I also having it in my left arm. What the devil is wrong with me?

Relax! I've noticed from my own experiences (this summer while I was testing and applying to medical school) that excessive stress cause you to have random muscle contractions (i.e. twitching). So if you're stressed out, try to relax... it may help :) .
If it continues or gets much worse, you may want to visit a doctor to have some blood tests done! Good Luck, I'm sure you'll be fine.