i always have trouble starting off a game story,title,ect, and i wanna make a mario & Luigi game
and i need help....

First, grammar, spelling, punctuation. Always make a game look good.
Second, know the cast. Don't give them personalities that aren't like them.
Third, learn from the examples people made. Mapping, animation, pictures, etc.
Fourth, wrong topic.

i also need a name and a story XD

Fifth, don't go on with something too unoriginal. Something like "Bowser's Revenge," or "Mario & Luigi 4" won't help you. At all.
Sixth, you can just be lazy and go with the stale "7 magical items of power," because it's pretty much common in Mario RPGs, but that'll give the game staleness. If you don't want something stale, don't go with "7 items."

yeah, but i need a "why" are they collecting 7 orbs, or seven stars or whatever....

To save the world from the items being used in the wrong hands? Or to defeat an evil being?
Seriously, it's not hard for one to understand these kinds of patterns.