Next time it freezes, I suggest to reboot and post your system journal log to see what happened. Since it is generally long, best may be to use pastbin.
The link in the post from @omano above should give enough instructions on how to post this information and other various system infos.
Edit: for example
journalctl -b -0 > ~/journal.txt && pastebinit -i ~/journal.txt -b lpaste.net
Or with system info
lspci > log.txt && lsusb >> log.txt && journalctl -b -0 >> log.txt && pastebinit -i log.txt -b lpaste.net