I suffer from sciatica but was given exercises by the physiotherapist which makes sure I don't suffer for long.
Be gentle, take it slowly and gradually
1. Stretch the hamstring muscle at the back of your thigh by leaning over in your chair as far as you can until you feel a pull on that muscle, gently does it, hold for as long as you can. Increase this by a couple of seconds every day.
2. If you have a bath, get out whilst still warm and bend as far forward as you can to get the same effect. It may not be far, just so's you pull a bit on the thigh...gently.
If you have a shower, do this at the end of the showering time when you have 'hotted up'
3. Lie on your side, the one which doesn't have the pain. Bend the leg on the side which does and push your knee, gently, towards the bed.
4. If none of these are possible, just try stretching your leg whilst standing at the kitchen counter or holding onto a chair. Just so you get that slight tension at the back of the thigh which will stretch the muscle.
She explained to me that the sciatic nerve is painful because the hamstring muscle is trapping it, so stretching that muscle helps free it and lessens the pain.