I tried to pull the knob up on our bathtub faucet to have the water go into the tub and it wouldn't budge. Any suggestions as to what is wrong and how to fix it?

Could just be lime scale or something making it stick. Try spraying a little bit of WD40 onto it.( Avoid overspraying onto the tub which could make it slippery) Tap on it gently with the wooden handle end of a hammer or something that won't mark up the finish?

Is it on the tub spout, right?

It's not a fun fix.

What is the brand of your bathtub faucet

i tried to pull the knob up on our bathtub faucet to have the water go into the tub and it wouldn't budge. any suggestions as to what is wrong and how to fix it?
You didn't inform us of the type of vale you have, so you're going to make me guess. I'm guessing a one handled tub valve with a shower pull up knob on the spout. There are two types od spouts one is a chrome over plastic slip on spout and the other is a chrome over brass threaded one,(see images) which one do you have? Waiting to hear, Tom PS. The slip fit I put up doesn't have a knob but you get the idea.