Did 18 miles and 4500' on Sunday and had some soreness down the outside of my left leg, from thigh down to heel. Fine on Monday, ran again yesterday night (7 miles and 2000' including a fairly aggressively run steep descent (from 3 Fingers Rock on Caradoc). Now have a very sore thigh on the outside. It's ok when I'm not moving, but sore when I walk or whatever. Pain is concentrated just below my hip.

Any ideas what this is or what to do about it?

Jim