I just got done using my iPhone heavily by surfing the net and making calls for the past hour and a half or so all while keeping the phone on charge. All of a sudden the touch part of the screen started to act up. It seemed to be only the bottom right quarter of the screen that was acting up and by acting up I mean it was hard to slide the unlock button and enter my passcode. Also while surfing the net while touching the same spot the screen started to jump and zoom in and out and just do some weird stuff. The back of the phone was really hot so I unplugged it, set it in front of the a/c vent to cool it off and turned it off then back on and now it seems to be working fine. Even though it seems to be working fine I am still concerned that there might be a faulty spot in my screen because this had happened to me on the 1st gen iPhone I had (I currently have a 3G). Should I be concerned? I got one of those $99 referb phones from AT&T and I only have a 90 day warranty. Thank you for taking the time to read this and your replys.