Bro..that's called malware or might be there are some apps/software causing unusual problems in your device..so first, update your device to the latest security patch, 2nd uninstall all unnecessary apps(especially 3rd party apps from not so genuine sources), 3rd scan your device, using inbuilt security system, 4th turn on Google play protect, 5th and the last, if you really feel that these steps are not helping, then go for factory reset..👍
