Are there rules about people who are loud and talking over players heads distracting those who are in game?
I was in a hand, a person not in the game was standing behind me talking to a player across the table from us loudly over my head. I found it very distracting to my game... I asked him to tone it down because I was in a hand and he was distracting me 😶 and he said he didn't need to.
Is there a poker rule about this kind of distraction while a game is in play?
No, there is no such poker rule in gerneral. Player behaviour is often covered in the so called house rules. Some rules which are can be found in the house rules:
If you feel disturbed by a person, playing or non playing, you can adress this to the dealer. He will surely take care, since you are the customer.
In your specific case the dealer could or should have as well noticed that you felt distracted and jump in. It's his responsibility to keep to game up and running. This also includes to remind non players to keep silence around the table.
Of course there are edge cases, if someone who is in the hand is talking a lot and it disturbes you. He is allowed to talk in general...
I always read house rules and see the tiny differencens since I use to deal as well and like to keep myself informed
