from your descriptions of symptoms you have an assortment of altered sensations and patterns of recruitment in your lower limbs, as would be expected from a low back stiffness problem, leading to irritation of nerves that arise near to joints. This is a common condition that is the natural and non pathological product of protective responses in and around spinal Wikipedia reference-linkfacet joints. The suggestions put forward that these events are somehow linked to perceptions of alignement or position of the sacro iliac joints are misleading. It would appear you have been mislead by a physio making claims about being able to interpret your condition on the basis of ilial or sacral postures. This is a spurious and nonsensical relationship which has only the loosest connection to the reality of Wikipedia reference-linkSIJ dynamics. Sacro iliac joints are somtimes implicated as biomechanicaly connected to lumbar protective responses and thereby to pain etc. To suggest however that these largely immobile ( though important ) joints can be "aligned " is the stuff of the purest fantasy.
Find a physiotherapist who is able to , by measured and skillfull attentions to the lumbar spine , turn of protective events there and you will find the means to a realistic way out of your painfull ( and doubtless confusing ) situation