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.