Iphone 7 keeps beeps and showing the home screen after every 5 seconds !!!! so annoying.

Dear all ,

For 2 days now my iphone 7 is really frustrating me. It keeps on beeping and showing the home screen after every 5 seconds. This has led to high battery consumption ( a full charge lasts only 2 hours). I have done the following to no avail. Uniinstall third part apps, reset the phone, perform a recovery , disabled all notifications to no avail.

Kindly if anyone can assist will be very greatful. TIA.