Pulsating feeling in lower back ?

[Ra88]

39+4 , had this pulsating feeling for the last couple of days on and off , it is painful but not sure if it is just normal pregnancy related pains or the start of something ?

Sounds like it could be nerve pain. That pulsating feeling could be because the baby is lying in a way that is pressing on a nerve, it can feel a bit like an elastic band flicking. It's very common once the baby is so big, unfortunately! I would try getting down on all fours and doing some circling with your pelvis and see if the baby will move positions a bit. It may not have enough room to move much but it's worth a try!