Pain when getting up from sitting/laying down

So.... I'm 16 weeks and I realize things are shifting and growing in my body ...but good lord. every time I get up from sitting or laying down it's almost painful, in my lower abdomen area. anyone else have this..? my doctor just says it's "growing pains" and when I said..okay but we have some more growing to do (due Dec 27th) he just chuckled at me. like no.. I'm not being funny. this is my first pregnancy.. so just looking for some reassurance I'm not insane. lol.