Has anyone spray painted the wood stock on a 10/22. How did you do it and how did it wear. Can I paint over the finish of the stock? I like the worn look and want it to match my AR15.

You can paint a wood stock.
It's a good idea to use fine sand paper to roughen up the finish to give the stock a "tooth" for the paint to adhere to.

Paint will wear off in areas that get handled a lot, but can be touched up.

Depending on how advanced you want to get, an epoxy based paint is tougher and more wear resistant.
Probably the best is Cerakote, but application is rather complicated.

Brownell's sell several suitable gun paints designed for metal, but many also work for wood.
Ordinary Walmart spray paints work well but as above, will wear through.  However, as above you can touch it up when it does.

Still another option are "texture" paints that contain tiny sand-like particles to give a better grip. This also wears somewhat better.
Some people have finished guns and stocks with pickup truck bed liner spray.
This is sold by Walmart and any auto store.
It's a tough finish that wears well and gives a good grip.
However, refinishing can be difficult due to the tough coating that's not easy to get back off and colors are limited.

I'm cheap and bored. The wood stock is perfectly fine but I want to paint something. Debating if I should just do it or not.

A long time ago I painted mine with one of those bedliner type sprays. It held up well for years.