I had them at 28 weeks and i had an ultrasound today and they said he is definitely down there to stay he's wedged himself so firmly there's no way he's turning again lol
its called "lightening" its the baby slowly dropping into your pelvis. which is good you want him or her to drop as low as possible before labour starts so the distance it needs to descend isn't as much which can lengthen labour.
When the baby moves she could be pushing on something in there causing you to get those pains... i had the same with my first pregnancy.