What Causes Sciatica Nerve Pain?

Yes, thanks .quastio " are following (1) why got sciatica ? the reasonis what ? ( 2) what is symptons ?(3) how can you find this desiaster and what kinks of test should to do ? (4) what kinds of tredments can help recovery .( 5 ) If after treatment ,could fell beter how can protect in furture avoid happen again ) ?
Please give your reccomdations and give me knoledges . thanks again !
Lily zhu