Hi
I had sciatica when I was in my early 20's. It started off with me not being able to sit down at my desk to do any typing for very long before developing 'pins and needles' pain down my leg.
To relieve it, I had to stand up all the time even to type which was a problem so I had to go and see the GP to find out what was causing it. He suspected sciatica but sent me to have an x-ray done at hospital which showed that my 2 discs at the bottom of my spine were touching on the sciatic nerve. I think this may have been caused by me stretching to get some suitcases down from on top of my wardrobe instead of standing on a stepladder.
I was off work for about 7 weeks and had physio done at hospital and was given a corset which helped and I went back to work with it on. After a while the discs and the nerve sorted themselves out and I was able to take the corset off and be ok again.
Its best to go and see GP and have an x-ray done though and not self diagnose as although you may have sciatica, your problems might be caused by something else.