Let me try again. In the code you have Serial commands intended to print "Motion detected!" or "Motion stopped!". Do they?. On the Serial Monitor? Did you try the extra Serial.print()? What results did you get?
I'm trying here but I can't see what you're doing or any results you're getting. You can't easily debug programs by just flailing around, it has to be done fairly methodically. If the Arduino is not detecting the PIR switching then nothing else is going to work so let's get that going first.
Steve