“How painful is a Discogram?”

YES, it WILL be painful, so ask your doctor for a couple of days of pain medication if needed. Also, I would be SURE that doing this test is NECESSARY and is REALLY needed for proper decision making (i.e., whether or not surgery is indicated and have a good chance of helping you). And keep in mind that, generally speaking, back surgery has AT LEAST a 50% or more chance of NOT helping reduce pain or even increasing the back pain.