What Causes Tremors In The Leg And Pain In Sciatic Nerve?

i have had severe tremors in my right leg and my sciatic nerve has been hurting for the past three days. i have had chronic back pain for the last 8 years (im 23) from an injury (minor fractures) scolio/kyphosis, bulging discs and facet syndrome. i have NEVER had this twitching or pain go down my leg, and its so bad that when it happens i cant even walk. help! my doctor wont call me back about it and its scary.