"Friends, I shall ask you to be as quiet as possible. I don't know whether you fully understand that I have just been shot..." That was the opening to a speech that Theodore Roosevelt gave in 1912 after surviving an assassination attempt. I mean, right afterwards. The bullet was still in his body. He apologized that because he was wounded, "I cannot make a very long speech," and then went on to give an extemporaneous 3,800-word address. Wow, that's one tough guy. Can you imagine any modern-day politician doing that?
This is quite a long speech, but it very compelling - especially the part where people try to get him off the stage for medical attention.
I have found it helpful to do the stretching exercises my physical therapist recommends. Do some core strengthening exercises, such as the ones highlighted at The Mayo Clinic. By keeping your core strong, your back won't put itself in a position to cause that sciatica pain you are having.