My iphone's screen froze.

My iphone Xr's screen froze this morning while i was looking on my Snapchat and after 6 hours it's still frozen.

The screen is frozen as i said and I can't do nothing; it won't force restart, it wont't connect to my Pc (i tried restarting it from iTunes but nothing happened becuase it wouldn't connect to my Pc), and even when i tried to just close my phone the screen would just go lower in brightness.

On the other hand i can hear my notifications and my ringtone when people call me, but again, i can't see from who because my screen is frozen on the same thing since morning.

Please help me, I couldn't find anything online and i don't know what to do!