Iphone 7 plus acting strange

Hello,my iphone 7 acting really weird,when i lock my screen all of its settings resets automaticly,lets say i make max brightness on the screen and lock my screen it will get back to minimum brightnes,and thats happen everytime i lock my screen,then in accessibility’s the assisting touch keep switching back on even i turn it off,so if i turn it off and make screen bright as soon as i lock my screen for a second everything resets,please help