I had same problem... I found the solution to my problem here:
Samsung Galaxy phone display Unresponsive or Black screen Fix - BlogTechTips
It was my freaking micro-SD card!!?? but the card itself works fine when inserted in to a computer... very strange.
Read the last paragraph in particular
Method 1.
1. Power off the phone and make sure it’s completely powered down.
2. Remove the back cover and remove the battery.
3. Hold down the power button for about 1-2 minutes.
4. Leave the phone for 10 minutes or so, go take a walk or something.
5. After the time has passed power on the phone again and that should be enough to restore things to normal including touch or remove the black screen issue completely.
If it fails the first time repeat the process and as an extra step remove the SIM card and MicroSD card from your phone as you attempt the procedure and then attempting to power up again.