The following people may ask you questions:
To help you give your evidence you will be asked questions, usually by a lawyer or possibly by a party to a case, if he/she does not have a lawyer.
If one of the parties disagrees with what you have to say, it is the job of that person's lawyer to ask you about matters of disagreement. In order to do so properly, the lawyer may suggest to you that you are wrong in what you say.
The judge or sheriff may also ask you questions. They may ask you questions about something that may have happened to you or someone else. Or they may ask you about something you may have seen or heard.