Standing positions tend to cause the spine to move into extension with the pelvis rolling forward (anterior rotation). If there is an Extension Impairment, the back may be unable to move further into extension, making it painful to stand.
Tilting the pelvis too far forward (anterior rotation) will also result in excessive back extension.
In your normal standing position, place your hands each side of the pelvis. Without moving the shoulders, see how far you can comfortably roll the pelvis forwards and backwards. Is it easier to roll the pelvis more in one direction or the other? Is your starting position in zone 2 or zone 3 or near the middle of zone1?
Try and find the mid point between the forward and backward positions and use that as your new reference position. Movement awareness exercises should be of benefit if they are practiced near your new reference position.