You could try the "David Bowie method". In a nutshell, take snippets from books, papers, poems, or anything really. Cut them up into chunks and rearrange. Fill in some blanks if needed.

As an obscure source of inspiration (works for any creative work, plus more I would thing), I'm going to also mention Oblique Strategies developed by Brian Eno.

https://www.oblique-strategies.com/
(Refresh the page for a new "strategy")

PS. Lyrics do not come naturally for me either and this is true for a lot of composers throughout the history. As a result, there's been many composer/lyricist duos formed.