My daughter had several when she was around 2 yrs old as well. The first of which I took her to the ER for because she was screaming, then went limp and would not respond to me and her eyes were rolling back into her head!
They did all sorts of testing and determing that it was a night terror, which they also gave me information about and explained that it was VERY common for that age and that she would outgrow it and that she would probably not remember having them the next day (she never did.)
They told me to make her comfortable, not to try and force wake her, etc. and to set a bedtime routine that was the same every night. She had several over the course of that year and they have never returned.
:( I know it is hard because it really seems like they are hurting, etc.!! Take her to a ped. just to be sure that is what is going on (let them rule out pain, etc.) and get some advice from the ped. as well if you can, or search the internet, etc. Maybe there is a yahoo support group for parents with children who have night terrors, etc. that you could join??
Best of luck,
Amanda (daughter to Pixie, now 6 yrs old)
PS- Often night pain in legs is a symptom of potassium deficiencies. This can be helped by eating bananas. ;)