The sciatica I have experienced is not the worst. It is certainly the worst physical pain I have ever experienced. Yet other people get far worse. I got acute (not chronic) sciatic pain down my right leg from the lower back to the top of my right foot and it got so bad I just could not find a comfortable position (lying down, sitting, nothing) and standing up was agony.
For the sciatica I've done lots of stuff and my personal 7 month journey went something like:
ow ow owa, call doctor, get valium (Diazepam) which relaxes this muscles so I could then at least lie down with much less pain and move around. I only took 3 of these tablets over the next few days. I learned I must not exacerbate the nerve pain and try to push through it like with muscle pain as it makes the condition worse and irritates the nerves.
I used a local osteopath (Marc) who is very gentle and does not do the cracking thing unless really necessary. My problem is lumbar 4 and 5 in the lower back. Found I could do some mat exercise and concentrated on strengthening my lower abdominal muscles. Turns out my Pilates teacher also does structural integrity (rolfing) which helped with the nerve pain.
Did all this and still the nastiness returned 4 months later. Not as bad as before, but I realised what was happening and stopped everything, took one valium and slept. Next stop was my osteopath who helped a lot.
I realised I must still be doing some stuff that was causing problems in my lower back. Did some more research on the web and found the "ab revolution" (a tad ott) and you don't need to buy the book as most of it's on the web: http://www.drbookspan.com/AbRevolutionSyllabus.html
I also did a brief scientific paper search and found some corroboration to this stuff - basically some people (like me) tend not to activate their core muscles when moving, like reaching upwards to get something off a shelf or standing up from a chair. So in my case I compensate in the lower back, which eventually does wrong, very painfully. I used mirrors to analyse my gait and found I had a dynamic issue during steps where my lower back would bend-through too much. So I changed my walking gait, habits of reaching for things, how I sit, stand and change and move. I'm still doing this as it takes months to form new habits. I changed to a variable height desk (this company does an affordable variable height desk that is good if you do not do much paper-work, e.g. use a computer, and offer evaluation tryouts) at work and now stand a lot of the day. Took a reclining chair to work and I lie down in it for a few minutes several times a day to let my postural muscles relax. I figured that we human creatures naturally change position all day long and staying in fixed positions is not good.
After months of trying I can now conciously relax muscles in my lower back and around the hips. When these muscles get too tense then I can feel the nerve pain starting to happen, again. In doing this I was guided by the nerve pain, and I used breathing combined with placing my hands on the muscles I wanted to relax and kept on trying, every day.
I work out 3 times a week, minimum, concentrating on core muscles (pilates, yoga and franklin exercises) and it's really helping. I still can't run for long as the nerves have still not fully calmed down and running irritates them (impacts) and it's a complicated movement that I need to change - it's a little difficult to use mirrors;)
Oh, and there's nerve flossing like this: http://8abs.com/guide-to-median-nerve-flossing-exercises/ which I learnt from a physio (self-referred as we can now do in Cambridgeshire). The physio was really great and we also went through a few of the fitness exercises I do and was having trouble with.