I have a g2

[AC Question]

I have a g2 and when i text or anything on my phone its like it has a mind of its on and the screen flip and it will go to different stuff and now the screen will also go black when i make a phone call and want come on for a while ibpull out tge sim card and push the power button and it flashes on and off but will finally come back on.. This is aggravating can someone please help.. I dont want to buy another phone this phone is awesome i love it so hopefully i can get some help and its a simple problem