Pinched Nerve

Hi Everyone,  I actually have a friend that is just getting started running again (I will soon have her converted into a trigeek), anyway, last weekend she woke up with a sharp pain in her lower back.  I had her write to me what it felt like.  I have no history or experience with what she's pretty sure is a pinched nerve.  I figured you guys might be able to help.  Here it is in her own words, any help is really appreciated!  "The pain is in the back of my hip, right above my , just to the left of my spine. It's a very localized stabbing pain when I lift my left leg (& my right leg if I lift my knee high enough
that it's parallel to my hip) & becomes a shooting pain if I try to run, and once I've stopped running it stays that severe as I walk for a while. The pain is internal, under my muscles (I can't press on the source of it with my fingers if I try), and has now gotten to the point where it's a constant sharp pinch if I'm sitting & no matter how much I twist around I can't seem to get to the point where I feel like I'm stretching it out."  She also noted that since she's been running again, she's been having calf soreness while wearing high heels and thinks she may be arching her back and overcompensating.