"Doing that is OK" is the normal SE policy.
But on this site I think that was overridden by the consensus/voting on this answer to the meta-topic titled, "May I share my research, by posting questions on this site and self-answering them?".
Sometimes, it will happen: when you don't know the answer, you post a question, nobody answers, you do the research, now you can answer your own question ... but (to avoid flooding the site with such topics) this shouldn't happen more often than maybe a couple of times per person per year.