A residence is a home you expect to live in for a temporary period, whereas a domicile is a home you plan to live in for an indefinite period. Any place you own property or live for a proscribed period can be your residence. But only the one site where you intend to make your permanent home and remain indefinitely can be your domicile. Thus, you can have many residences in many places, but you can have only one domicile in one intended place. based on other posts your domicile would be PA. you would file a resident return. there while filing a nonresident return for SD, do SD return first so you get the proper credit on the PA return for any income taxed in both states.
you didn't say what the property in SD is used for - if rental so there is a question of whether you even need to file a SD return
