My phone keeps lighting up while it is locked like as if I hit a button. If I set it on the table, untouched, locked, it will light up by itself, showing the lock screen, and then go back to a black screen. Then anywhere from 10-30 seconds it does it again, and again, and again. I think that the home button is acting up because when I hit it once, only for a split second, it will show the open tasks page, then it will go away fast, even if I don't touch anything. It has been doing this for about a week and it is just killing my battery. Any ideas on how I could fix this (hopefully without having to buy another phone or pay for insurance to fix it). Thanks!!!