Hi Lucas,

If lying on your back and lifting up one leg felt the same on both sides in terms of effort and strength, then it is unlikely you have done an Wikipedia reference-linkSIJ joint. Don't get me wrong, i absolutely love treating SIJ problems but yours sounds like a disc problem.

Some reasons why from what you have written (limited informatino clinical reasoning ):
1. Discs are the main restraint to twisting - this seems to be the worst movement for you. Wikipedia reference-linkFacet joints can also be inplicated but they tend to be sore in backward bending...
2. Disc injuries are most commonly sore in forward bending - like you describe
3. SI pain from ligament injuries are usually sore from the PSIS down to the sacrotuberous ligament. This is most commonly referred to as Fortin's area of pain. He determined SIJ pain referred into this area by using injections into painful SIJs.
4. SIJ pains rarely refer into the hip joint. This more likely to be the L/S discs/nerves/joints doing this
5. A SIJ ruptured ligament will be difficult to stand on one leg - the main job of the SIJ is to transfer the load from your foot to your pelvis and up your spine and vice versa. An unstable SIJ will not let you stand on it.
6. Hip movement is likely to aggravate the sciatic nerve as it passes near the piriformis muscle.There are also other muscles nearby that can tension the sciatic and other nerves. SIJ pain is over the SIJ.
7. Crossing legs on the floor usually posteriorly rotates your pelvis which would strain the disc.

Quite simply, i do not believe (from the limted information we have) that you have an unstable SIJ. You would need SIGNIFICANT trauma to disrupt the ligaments there. You may an SIJ dysfunction but i do not believe it is causing your current pain. You sound like a classic disc patient to me. An Wikipedia reference-linkMRI or CT scan can quickly solve this problem. From the sounds of it, the disc has probably herniated which is why you are in so much pain - the noxious chemicals of the disc are irritating and sensitising the nerves.

My money is on a disc problem - anyone else??