Hello- I am a 21 year old female and for the past few months I have been experiencing some lower back pain- but it seems to be radiating down my right leg as well. When I sit I feel the pain in my butt and it is umcomfortable for me to sit down on hard surfaces for a long time (which is hard because I am taking a 4 hour class- 5 days a week) I have gone to my chiropractor and he says if my condidtion does not improve I will have to go for an mri to see if something is interferring with my sciatic nerve. I have a couple questions and hopefully someone who may have experienced this type of pain can clear things up for me:

1. I have done some research on sciatica information and it seems that most people feel pain down the back of their legs- but a lot of my pain seems to go into my knee- when driving or sitting in a car the pain in my knee is almost unbearable- I was wondering if knee pain can be associated with this diagnosis.

2. Along with the back and leg pain I have also had pain in my right lower abdomen and I was wondering if sciatica can cause this pain as well. It's so low almost to where my hip bone is- and I have gone to the doctors a couple of times worried that it may be appendicitis or something along those lines and cat scans and ultrasounds have ruled out anything like that. So would just like to know if this could be related or I should be further investigating this abdomen pain as something totally unrelated!
***so any help as to what could be causing my problem would be greatly appreciated- thanks for your time