Trunk lock won't open '90 80

[Al S]

My trunk lock has stopped working. It was fine the other day, then today it
would not work
with the door locks unlocked, so I turned the key to the right and unlocked
the trunk.
I took the cover over the locking area off, I didn't see anything broken, so
I closed the trunk. Now it won't unlock with the key turned in either
direction. Yes I am using the right key.
Can I get into the trunk by removing the back seat or is it better to take
it to the dealer?
Thanks,
Al