my 3mth old girl keep sleeping on her right side since birth and now right side of head is a bit 'flat' and some advice me to let her sleep on yaolan... will she be relied on yaolan? should I let her sleep on yaolan? troubled....

Have you tried repositioning her head and "training" baby to sleep on the left side? One way you can do this is to push baby's crib towards the right against the wall. Naturally when baby is lying in the crib, she will want to look out and might just turn to the left since her view is obstructed on the right. Also when you're feeding her, perhaps you can alternate between sides? This will train baby to work her left side muscles.