Difficulty breathing

Ashley
I'm 26 weeks tomorrow, and as of late whenever I lie on my back or even on my sides (flat) I experience shortness of breath and I'd have to elevate my upper body with pillows to feel better. Also I've been experiencing some sharp pains on the right side of my ribs... Is this normal or should I be contacting my OB? 
I ask because I have a 12cm fibroid that is growing as baby grows, and I was told that it could affect baby's growth and even determine due date, so premature labor...