I am a 19 year old that is about 116 pounds and 4'10". For the past couple of months, I've been experiencing pain shooting down my left leg, as if it is along my sciatic nerve. the pain usually spans down to my knee, and the area just to the left of my tailbone is in constant pain. When I bend my knee so my leg comes straight up toward me, something pops inside of my hip area. it is not something that can be felt externally, so it may be happening further within.