With my 2nd baby, I felt like someone had just taken both of my legs and used me like a wishbone. You have been given a great deal of good advice on dealing with the situation if that is the type of pain you are dealing with.
If it is sciatica, it will be more on your back in the hip area than on the side, and you can just tell that it is muscle-related rather than bones. I had a horrible time with it with the last pregnancy and it never really went away. I finally wound up having an accupuncture treatment and deep tissue massage (this was 6 years after I had the baby btw). It was amazing, my sciatica had hurt every single day since my last one was born but with a single treatment, I haven't had any problems with it since.
In addition to everything else, hot baths are good whether it is muscles or bones. And if it is a muscle thing, you have the added bonus of the wet heat helping to relax the muscles and actually make you physically better so less pain to deal with.