Understanding Writing. How to Write. Knowing Writing

I has occurred to me, at the age of 38, that I don't understand writing.

Now before you get your daggers out, know I'm not referring to the grammar and structure of writing and English. I understand that.

I'm more referring to "Why am I writing?" "What should I barrel forward with?" I don't know. I wish I did. There's something I don't understand about fiction writing in specific. I wish I knew how to do it better, and for longer periods of time. I have no stamina.

Sure, I've written a lot at the age of 38. And I've been writing for a long time, but that's not the same as understanding the meaning and technique of what you're doing.

Good Day, Sir...