A few minutes ago i posted a question but doesn't appear on the screen yet?

It is a glitch when the question is listed in your My Answers but not showing in the Category you published it. First check it is in the proper category. If it is then moves it to another category and waits 10 seconds and move it back to the original category. Check and see that it post. That will solve your problem.

Move it to another category, wait a few seconds, and then move it back. If that doesn't make it visible to others, try a small edit or update.

It's hung in the spam filter, which happens to some answers as well.

Give it some time it may not have gone through the Filter Yet

Change the category and then change it back