Breathing issues but only when sleeping? Will it pass?

It’s a little odd to explain but I am 4 days post op. I have been sleeping upright. So far the pain has decreased immensely, however when I try to sleep I literally am feeling air forced out of me, like if someone where to suddenly push on me. The sensation would wake me up. It’s exactly like if I were to exhale really hard. I am not having any issues like this while I am awake and have never felt anything like it. Thank you! 5’3 approx 58kg, 385cc under muscle