To jacinta

I have some guesses why the neurodynamic tests did not test +ve
1) because the protrusion was not large enough and the dural sheath rather than the nerve root was irritated. A crossed leg SLR may have helped to confirm a compression
2) because a significant amount of inflammation had reduced before any of the tests were undertaken

When there is a low back pain with multisegmental distribution of pain (as described by you, downward and upward referrals), the dural sheath irritation should be suspected.

it sounds like your treatment so far has focused on resolving the abnormal biomechanics that may have caused some stress in the low back hence the minimization of pain. It is not uncommon to have low back problems that never start with the low back but emanate somewhere else. Cyriax techniques mention this phenomenon.