89 420 sel with 205k

About two weeks ago I unlocked the doors by using the key in the driver's door. Somebody stopped me to talk and a few minutes later I attempted to open the door and found all of the doors were locked. Since that time, every time I unlock the doors (driver's or passenger) they will stay open for about 5 seconds and then every one locks again. In addition, I can no longer get the trunk open at all. I tried the key in the lock and every thing seems smooth and functional but it will not open. The only idea I've come across reading posts involves a 2x4 and a hammer so I'm hoping someone will have another idea before it comes to that.