Iphone 5 problem! Its like a ghost is touching it?

I have the lastest ios update on my iphone 5 and it crash all the time but since yesterday when i'm using the iphone ( touching the screen ) its like someone is touching it too its for exaple it touch a app or go to phone touch number, and use the keyboard but it stops and 1 minutes later it start again!

You have an issue with your digitizer. The digitizer is the layer of the screen that is responsible for capturing the touch input and then relaying as a command. If you haven't done a hard reset on your device yet I would start there. BACK UP ON iTUNES! You could try replacing the screen, and if that doesn't work you may have an issue with the logicboard.

Are you using a case?