i have never played a fallout game but keen to pick up new vegas will it be easy to pick up storyline what is the chronology is it even a sequal to fallout 3 can someone give me a good explanation

Their are probably only a few people who loved Fallout 3 for the story;

Their is not much to known;..just that their was an nuclear war that fucked up the world and you have to survive in it;....You create your own story :).

The Story from fallout 3 has nothing to do with new vegas. I also think that betheseda is making a fallout 4 so the story wont be a problem.

Go to Wikipedia if you want to read about the fallout games.

Or "The Vault" Wiki has some excellent write-ups.

http://fallout.wikia.com/wiki/Fallout_Wiki

It makes no difference, I don't think you're even the same character as in Fallout 3. I kinda missed part of the opening cutscene though.

Here I'll fill you in on Fallout 3 though. You escape vault 101 to go look for your dad, find out he's involved in a project to purify drinking water on a mass scale, and then you join up with him and get it running. There's some other details too but that's basically all that happens. Its a game that's big on gameplay not story.

here is the backstory you will require:

the world has been through a nuclear war.