Since I installed iOS7 beta 2 version, my touch screen started to go unresponsive from time to time. After a couple hours of internet research this is what I found:

iPhone unresponsiveness is mainly caused by notification messages being sent behind the lock screen. For example, when your battery reaches 20% you get a notification on your screen. There is a bug that may send those messages behind the lock screen giving you as a result an unresponsive screen – your iPhone is waiting for a response, but since you do not see the window because it is behind the lock screen, then you cannot respond… and well, you know.

How to fix it

• Try to use Siri. Ask her to launch an application like “Contacts”. This works most of the times.
• Wait until your battery dies and connect it to the charger.

Things that will not work

• Restarting your iPhone will not work. It does not matter how hard you try, it will not work.

Recommendations

• Do not let your battery go under 30%. Take your charger with you.
• Other apps may lead to a similar behavior when they ask you things like “App X wants to access your contacts”. Do not procrastinate your responses.