[Q] phone shut down by it self topic

hellp can any one help me fast
so i flashed the touchwiz reveloutin rom and it was all good untile after a couple months
the phone get shut by it self like i am using it suddnley the screen go black and i see the device name so i think it was from the rom so i flashed the stock back and the proplem still happen :confused::confused::confused::confused::(:(:(:(