if the trunk lock mechanism is sluggish or stuck try gaining access to the mechanism and spraying it with penetrating oil. Wait about a day or so and if you want spray it again and wait another day.
Or use the key and easily try to work the lock, not too hard though, you don't want to break the key.
I've heard of a few people that has stuck or sluggish key locks on the trunk and a quick spray with some penetrating oil brought it back to like new.
