I had the same issue. My doctor told me to get on all fours for a few minutes and since the baby hangs there in a sense it will take the pressure off of your lungs and loosens things up a bit. I tried it and it worked wonders!
I have the same issue. I feel like an elephant is sitting on my chest. I'm assuming it's bcuz baby has pushed around all my organs. I'm going to ask my doc at my next appt. If u get more answers plz send me a note! By the way Im 32weeks
Baby might be sitting high and compressing your lungs a bit? Try not to exert yourself so much that you have trouble breathing. If you're concerned, talk to your doctor.