Are hotels allowed to give out private guest information to an unknown person ?

You need to post what harm ensued. Did you instruct the hotel that all of this was confidential? They cannot read your mind. If the information about you can be found through other means, you will have a very difficult time convincing the court that this was confidential information to be protected. On the other hand, if you were the victim of domestic violence and this inquirer intended to harm you, you may have a much stronger case.
You might find my legal guide on Is it Legal? Is it Illegal? helpful.

LEGAL DISCLAIMER
Mr. Sarno is licensed to practice law in NJ and NY. His response here is not legal advice and does not create an attorney/ client relationship. The response is in the form of legal education and is intended to provide general information about the matter in question. Many times the questioner may leave out details which would make the reply unsuitable. Mr. Sarno strongly advises the questioner to confer with an attorney in their own state to acquire more information.

These comments are made for educational purposes only and do not constitute legal advice. No attorney-client relationship exists between us.

You can’t sue just because you are worried that something bad might happen due to the release of the personal information. Unfortunately, something bad must happen and you must show that it resulted from the release of the info and that you had damages.

Start by getting credit reports from all the bureaus. Do not request them on-line because some have arbitration clauses buried in the terms of use. This is important if the bureaus fail to correct the error because you can't sue them if there is an arbitration agreement. The reports will let you know if any unauthorized activity has occurred.