I'd like to pre-bake pita bread so that I can store it in the fridge and use them one at a time by heating them in a pan. Any idea how to do that?
First off, I'd recommend not refrigerating pita if you don't have to. It tends to get state quickly. Pita should be safe at room temperature for several days. If you're keeping your pita longer than that, you should freeze most of them. Leave them to defrost on the counter before you intend to use it (it will take a few hours to defrost, and will be good for a few days).
If you're trying to heat it up, you can use a microwave, if you have one. It doesn't take much; start with 20 seconds and see if it needs more. (It will vary widely between pitas, microwaves, etc.) You can also use a conventional oven; wrap it in aluminum foil to keep it from toasting.
If all you have is a pan on the stovetop, set it to medium-low heat and cover the pan. Heat it on one side for a couple of minutes, then flip it over.
I normally make a full batch of pitta, freeze most of it and then defrost using the toaster.
Contrary to Joshua Engel's answer, I've never had any trouble with the pitta toasting rather than defrosting; for contexts where I want pitta I'm happy for it to be hot. My toaster has a 'defrost' setting which I think reduces the heat intensity, and I'll typically set it at the shortest setting, then turn the pitta over to heat the part that was sticking out of the top of the toaster. I also sometimes leave it in the oven for a few minutes to defrost instead but have never felt a need to wrap it in foil beforehand, and I don't think it's suffered as a result.
I've never pre-made pita before, but I'll see if I can help. You'll have to cook the pita all the way the first time you make them, if it is going in the fridge there can't be any dough. To reheat them I think a low to mid heat in a non-stick pan or lightly oiled pan with the lid will help you warm up the pita. Give it a flip or two and I think you'll be good to go.
As with most of my cooking adventures I think the best idea is for you to try it out. Make a small batch if you are worried. You could potentially use the oven again to re-bake; that would work well if you already are using the oven.