Hard to take deep breath while pregnant

I’m 19 weeks and a couple days. I got my ultrasound just the other day and they said everything looks perfect. I get shortness of breath off and on- probably more at night which I know shortness of breath is normal. Although sometimes when I am short of breath I have a hard time to take a deep breath or finish a yawn to where I’m satisfied with it. Is this normal and part of the shortness of breath?