1099 with work in Multiple States

[yagra6719]

I have a single owner LLC that is used for consulting business for customers located in multiple states, including OK, MO, and PA. All work is performed remotely from office in IN. Yet in the three noted states, the customers included state/source income on the 1099. Must state returns be filed, and state taxes paid, in those states? What is the proper way to handle this?

[Anonymous_]

@Mike9241