Every so often

Every so often it bursts
opens up that part of me
where history hides memories of pain
wrapped in a scent
or in the lyrics of a song
or a day in the calendar
or thought of a time past
or compassion for a ghost long dead.

And what key opens this part?
What lock is it that opens too readily?
Why if only I knew,
for the key I would throw
and the lock would stay closed
and the tears would dry
and the grimace fade to a smile.