I am trying to go from an older light in the bathroom it has a pull switch to a vanity light that requires a wall switch. What I have tried is I ran the main wire to the wall switch and vaniety light and tied them together... When I went to turn the breaker back on it keeps throwing it any help would be greatly appreciated

If you have run a wire from the vanity light switch to the old light, or th evanity light to the old light, then it will be possible to do what you want... but you'll have to provide some more information.
1) How many wires are in each box, and what colour are they?
2) Which wires are connected together?

There's three wires black, white, and ground, all the lines have the same colors, the main line is attached to the vanity light as is the one coming from the new switch something like a jumper. So the switch does not turn on or off it stays on and throws the breaker as soon as we turn the breaker on hope this helps the black wires are together, the white are also and the ground wires are grounded.I am sorry I have gave you the wrong information the main wire has 2 wires.. 1 black and 1 white hope this helps

I hope I can shed some light on this problem -- correct me if I'm wrong

You had a vanity light that had power and was switched with pull chain

You also had a ceiling light that had power and was switched on wall

You have two circuits and you want to switch both from existing switch

You ran a 12-2 wire (example) from switch to vanity light --?

We still need more info, even a diagram. How many of each color of wire in each box? What colors of wires are connected to the switch? It sounds like you may have tied a hot white in a switch loop to the white neutral. Current code calls for such a white to be marked black.