I am a W2 in IN, working in IN. I had a temporary W2 job in CA that was remote, working from IN. I never went to CA for work. Did I make money in CA too, or only IN?

You made money your money in IN, where you worked, not in CA where your employer is located.

 

Wages are considered as earned where you perform the work, not where your employer was located.

 

You would only file a CA return if your employer incorrectly withheld CA tax from your pay; in that case, you'd file a CA return only to get a refund of any CA tax withheld.