Is my iPhone 4 touchscreen malfunctioning? My iPhone4 is weird. The bottom touchscreen can be slid (to unlock) but it's really hard to tap the app in the bottom area. It seem the bottom screen is not sensitive but I can slide to unlock. What's wrong with my iPhone?
There are a handful of utilities that you can use to test responsiveness of your iPhone.

Try using a webapp called Sparky in order to test and see if there are in fact dead spots, alignment issues, or any other problem with your iPhone's touch screen.