I cracked my iphone 4 and the touch screen is uncalibrated?

Okay so i accidently dropped my iphone 4 and now its got cracks in the screen. It wouldn't bother me (that much) but the touch screens messed up. Like when i press on something it goes on something completely different. I can't afford to fix it.i've heard if you press the back of the iphone, the touch control things works again? Does anyone know how to get the touch thing working again? (calibration i think it it is)

There's no calibration on Apple touchscreens. The screen has 2 pieces called:
1. LCD
2. Digitizer (Glass)

The LCD is the screen you see, the digitizer is a transparent film that keeps track on where you touch. If it is not registering correctly, then the digitizer is damaged. You can tell which is broken by looking at it. If the glass is broken then the digitizer is damaged, if the actual SCREEN is broken, then you can't see anything, or the image looks bad. If your LCD (image) is good, but only the glass is broken, you can buy a digitizer from amazon and replace it, its only 20 dollars.
http://www.amazon.com/...B003UGVU4G

If the screen is broken as well (LCD) then you have to replace both and its a little more expensive $26 dollars
http://www.amazon.com/...004GVYXP2/

The tricky thing is changing it yourself.