After tests to ensure that a) both sides of my body react to stimulation the same way and 2) certain flexes of leg/hip/ankle/neck weren't causing pain or numbness in my legs she said she was able to rule out disk/nerve issues. She then put her hands on my hips and had me raise one leg at a time, at which point she said she knew the cause. Apparently the sacroiliac joint on the right side of my pelvis is frozen, while the left side flexes normally. This lack of mobility in the joint causes the muscles to have to work much harder and stretch more, which is causing the pain. And she told me to get my Costanza-like wallet out of that back pocket . She did some mild electro-stimulation and performed a few treatments (drop table and others) to start "unfreezing" the joint and treating the muscles.