Stabbing "electric shock" pain in the back of my thigh

[juliannabeanie68]

It began yesterday - this incredibly painful throbbing feeling - like electric shock, in the middle of the back of my left thigh.  They last anywhere from a few seconds to a few minutes.  It hurts to the point it I feel sick to my stomach.  It's always in the same spot - and it's very rhythmic.  I was wondering if anyone else has experienced this?  I have a very high pain threshold and this is probably an 8 on the pain scale while it's happening.