L.S.
my joints weren't stiff per se, but my pelvis was definitely different. it still doesn't feel like its all the way back together again. and if i move certain ways it pops & cracks. but my back was sooooo outta wack and it still is. my son was almost 10 lbs at birth and he's a big kid now (about 35 lbs, 22 mos old).
your condition sounds important enough to be checked out.
take care,
rah