I have recurring sciatica pain, what is the best back/leg/lower body workout

My sciatica pain keeps coming on and off either during workout or at work, I work in a catering business which requires lifting.

What is the best leg/back/lower body workout for me? I would like to do squats and deadlifts but I'm afraid of hurting my back.

Focus on unilateral movements first and also stretch your hip flexors. watch these videos http://www.workouttrainer.com/home/videos/wtjuly00-4 and http://www.workouttrainer.com/home/videos/workout-101-stretching-the-hip-flexor