The restraining order itself usually expires within 1 year to 2 years depending on the state.
But even when the restraining order expires it still shows up on your record and to get the restraining order off your record you need to hire an attorney.
The attorney will work with the court and try to make contact with the person who put the restraining order into place and hopefully get it removed.
Usually if you haven't had any other problems with the law or haven't ever violated that restraining order then you might be able to get the restraining order removed from your record.
You can contact the courts directly but you should hire an attorney who knows what they are doing and they can usually get the restraining order off your record pretty quick.
The attorney will cost some money but it's worth it to let an attorney do most of the work at getting the restraining order dropped from your record.