I get sciatica from time to time and the thing I find helps best is an exercise to open up the spine to help release the trapped nerve.
It's a standard yoga exercise where you get on all fours and then arch your back up at the same time as lowering your head-but SLOWLY!
I then reverse it - head up and back concave.SLOWLY and just repeat a few times ending on the arched back one then get up SLOWLY!
YES I'VE CHANGED, PAIN DOES THAT TO PEOPLE.