Have you or anyone you know, had these symptoms?

Excessive, horrible leg pain....deep in the muscles, daily. Aching and searing and as if you ran a 1,000 mile marathon without stopping. :( Plus, constant, daily twitching in both legs too. No test shows anything..MRI, Cat scan, even extensive blood work.
My sister is a diabetic, experiencing these , and most of the doctors have said, it's not neuropathy or diabetes related. ONE doctor said, it is neuropathy. So now we are stuck yet again. She's hopeless, with no doctor knowing what is wrong. They say join a study, but don't help her to find any. It's an awful cycle, gone on for 8 years. She wants to die most nights, b/c it is so unbearable. Anyone ever have these symptoms ?