1999 Saturn SL2 Clicking sound in the trunk and car will no

1999 Saturn SL2 4 cyl Two Wheel Drive Automatic

Sometimes when I get into my car, I hear a clicking sound in the passenger side of my trunk. Then when I try and start it, I will not start. After opening and closing the trunk a couple of times, the noise will stop, then in a while the car will start just fine. Also, the automatic locks will not work until the sound stops but the radio/lights will. What is causing this noise? Should I get a mechanic to look at it, or not put anything in my trunk?