yes you can change question from open to close because option is available below the question
Of course, what needs do is just check down the question and you see the options
Thank for answering
yes you can. But you get points for every view so i wonder why you would do that!
you can immediately try it, it can be done. but as bernardbear say, for what you close it
Yes ! you are only the person who can close your question yourself. May be ADMIN can also do the same job.
Yes, you can close your opened question. But @bernardbear is right at the same time. Why you want to do so? while other members want to give their comments,
Yes @shazadmalik you can use the Public symbol to the right side of your Q&A and edit or delete your question.
Thank you @ardodd for clearing your answer by mentioning the right options and position.