There was a story line from the 90's where Tony's armour gains sentience and begins making decisions for itself even who to target. We see in the trailer Tony mentioning that he can't sleep and that he has a new headset interface, so I'm guessing this is a homage to that story line. He also suffers a heart attack in that story IIRC. I'm assuming this is where he will go to Maya Hensen and ask for her help in developing the Extremis technology. Just my own guess though. As for the symbol tattoo on the back of his neck, it doesn't ring any bells...it could be his own personal clan symbol (that's just a guess). I'd need to see it blown up to really be able to tell.