iphone8 plus

I got an iPhone 8 Plus not long ago and my camera is lagging when I try and take a photo it has also been shutting down even tho the phone is fully charged i tryed the same thing on my friends phone and it does not lag I don’t know why it does that I have not used a lot of storage on the phone and i don’t know what’s going on with it any ideas on what I should do or what it happening