Lopsided belly, normal?

Brittany

I am 20 weeks and the last 5/6 days right when I lay down from being up for a few hours my left side of my uterus is much bigger. It’s also harder on that side and then after about five minutes it’s all good. It’s becoming more often and daily, is this pretty normal, just because baby is getting bigger? I figure it’s just baby preferring that side.