I've had sciatica for 25 years. I've got a ruptured disk that presses on the nerve. I manage the pain with exercise and stretching. It has never stopped me from sitting in an exit row. Even when I have pain, it doesn't impact my mobility. Yes, I can lift 50 pounds. (Though there was a guy on my flight to TLV who was really upset when the FA moved him out of the exit row, sitting beside me, because one finger was in a splint.)