Epistle

You might pen down your thoughts in a story, poem or even a quote, but someday, if you wish to pen down your heart, try writing a letter.
You can address it to yourself, or an imaginary friend, or perhaps to the universe.
It has worked for me, always.
Writing a letter is like opening an emotional faucet, everything you've been storing comes rushing out, unfiltered, depending on the provenance. Try it sometime, feels relieving.