I had my first lumbar sympathetic block on 9/30. i was completely pain free on 9/30 and 10/1. my pain came back this morning. should i consider a 2nd?

Talk to the doctor: Well, unfortunately, that's one of the drawbacks of these sorts of injections. Let's assume for a moment that operator (the injector) did everything absolutely correctly, used the correct dose of medication, and the placement was impeccable....in fact, your pain was gone for 48 hrs. But then, it reared it's ugly head. Sometimes that happens for unknown reasons. Notify the doctor.