Hi, I need to build a wall around my garage door and still be able to use the door.
I have finished the garage into a functional room however I still need to use a portion of the room for lawn equipment and such. I need a plan for framing out the wall and including a door to be able to get through to the smaller room and out of the garage. The garage door has rails on either side which the door rides on and nothing in the center. Anyone have any ideas? Thank you in advance for any help with this difficult project.

In a lot of locations you are doing to need to pull permits and have the zoning people involved. A garage is not considered living space... but section it off and technically it stops being a garage and becomes living space which changes your tax calculations and valuations.

Please draw a picture or describe more clearly.
You say you have already built a 'finished' room in the garage... I take it that you want to build a small storage area on one side, but the partition will hit the overhead door. So you don't build it all the way to the ceiling, right? A 7' high wall? Two walls, perpendicular to each other, one covering the garage door, and one closing in the equipment, with a regular 36" door in it? A regular door is 6'8, allowing 4" for the header. Assuming your overhead door is at least 7' high when raised. If it takes up more room when curving up, the wall you put up in front of it should be far enough back to handle that. You say you have to be able to get the equipment out that door, right?
I just don't see why this is hard.

Build a U shaped wall with a door in one end.