Q: My iPhone 6 plus has been restarting by itself at first it was because of that one "power text" but now it does it randomly

I can be using a app or having a call & it just restarts by itself it's been happening a lot sometimes even more that 3 times a day & i don't know if my phone messed up because when the "power text" was out a lot of my friends would sent me that so my phome would restart & now I don't get those texts anymore & it does it by itself