The back upper part of my iPhone gets very hot whenever I use it.

The back upper part of my iPhone gets very hot whenever I use the phone. It basically renders the phone and apps useless. I could not maintain gps directions for a 15 minute drive! This has been happening since the new update, and I have noticed in my online searches (on iPad) that have many people have the exact complaint. I have turned off all app refreshes, gotten rid of all widgets, and deleted many apps, pictures, and videos. I have shut down and restarted. I don’t sit in the sun with it. The room temperature is between 68 and 75 degrees F. Within 3 minutes of using it, it gets very hot to the touch. I’m constantly putting callers on speaker because it gets too hot to hold to my ear! And sometimes I loose the call! Apps come up blank or shut down. Can you tell I am frustrated? My phone went off warranty a few months back. I think an $800 phone should last more than 18 months! So back to my question:What is Apple doing for customers whose phones are overheating since updates?

[Re-Titled by Moderator]