What does the "Total of all your payments and withholding" refer to for a state tax refund? Is it referring to the specific state refund, e.g. OR, or all states to which states taxes were paid? Thank you.

It refers to the payments and withholding for the specific state that the payments and withholding were made to. So if you are preparing an X state tax return, you enter the payments and withholding made to X state.