My dodge stratus car alarm keeps going off on 2003 Dodge Stratus

My 2003 dodge stratus car alarm has gone off 5 times in the last day. I only have a key to it, not the keyless entry. I've tried starting the car and it won't stop. It goes off for about 5 minutes and stops. Can some1 please help me?

Asked by for the 2003 Dodge Stratus
Assuming this is a factory equipped alarm, Try unlocking the passenger door to stop the alarm. If this works, your key position switch on the driver's door (inside of the door) is defective. You should purchase a remote as a backup.
If this is an aftermarket alarm, refer to a shop who installs them.