I'm 40 + 3 today and since I woke up this morning I've had a pain across the bottom of my ribs…

I'm 40 + 3 today and since I woke up this morning I've had a pain across the bottom of my ribs (right under my boobs) when I breathe in or if I sit a certain way... It's not constant, only getting the pain when I move a certain way or breathe in deeply, what could this be? Had a feel and can't feel any baby parts that would cause it as she has dropped... Was going to ring the doctors tomorrow if it hasn't gone by then xx