Sore belly in morning

Talia • FTM with baby girl! Due December 9th
My lower belly is so sore every morning when I wake up. It feels really tight from the inside. Or that feeling when you're full of gas or something lol sometimes it radiates to my lower back too. Im 16 weeks 2 days with my first.
 It makes getting ready for work every morning really hard! I have to sit on a stool the whole time. But it seems to go away after an hour or so. Anyone else?