Dumb question, but can I lube my seat belts?

Hi All: The passenger front seatbelt/shoulder harness in my 74 Duster is all locked up. I can't get it to pull out properly to belt someone into the front passenger seat. Both the seat belt retractor, and the shoulder harness retractor are locked up on the right side. Does anyone know why this happens and what to do about it? Thanks - BOB