What Causes Frequent Feeling Of Heavy Chest Causing Constant Yawning?

Hi, I keep yawning but not because I am tired. I feel like I am not getting air and keep needing to take deep breaths but no matter what I feel like I can t get enough. It feels like something is sitting on my chest. This happens sporadically usually a few days at a time. However, it has been about a week now and gets worse in the evening time.