LOCKSCREEN FROZEN AND REBOOTING.. HELP ME! please

ive never had any problems with my new iphone.. i have never done any self damage to this phone and all of a sudden when ever i tried to open the lock screen it freezes, it will freeze for 10 mins approx., then reboot.. can anyone help me??

** note i cant connect to my wifi at home anymore for some reason so therefore i have not been able to back up my phone... could this be the answer?**