Establishing the Character

Players Handbook (page 34)

By determining abilities, race, class, alignment, and hit points you have created your character. Next you must name him or her, and possibly give some family background (and name a next of kin as heir to the possessions of the character if he or she should meet an untimely death) to personify the character. Having done all that, your Dungeon Master will introduce your character to the campaign setting. In all likelihood, whether the locale is a village, town, or city, your character will have to acquaint himself or herself with the territory.

House Rule

Depending on your character's race, there are limited locations from which they may originate. The campaign has been set up so that there is a primary home region for elves, dwarves and hobbits. While there are communities of these races mixed into towns and cities, it is advised that this is not their background as their are additional benefits from the experience gained in your natural home setting.
Humans and half-orcs are more varied, and your class may dictate some of your experience.
Player characters will not be high-born. That is they will not have a background of having status in the community, parents as leaders, or significant title. Likewise, charcters will not come from poor backgrounds, as they are unlikely to have the goal of an adventuring lifestyle. A low-life who takes on a thieving career, is likely to be tied to the thieves guild for life by both debt and for security, and unable to ever break free (without a price on their head).
As it is, your campaign starts with you skilled, but inexperienced. You will have travelled little beyond your home territory, and in general you will have made a single direct journey from your home to the campaign start point. You will definitely not have any history with any NPCs. You are not Conan, where your family were wiped out by Thulsa Doom and his men!
The DM will discuss privately the options available to you for your character back story. Only you will know this and the decision will be yours for when and if you want to divulge this with your fellow adventurers.

DM notes Starting the Campaign