Short of breath in third trimester

I am 34 weeks and 4 days pregnant. I started to get short of breath for no reason around 30 weeks. As the days go on, it’s happening more and more frequently. Sometimes my chest gets achy and sometimes my back gets achy. Sometimes it’s a combination and I feel jolty type pains in my chest and lower back along with the difficulty taking deep breaths.

I plan to discuss it with my OB tomorrow but I’d like to know if anyone else has experienced this either. My doctor tends to call everything “normal” and it’s frustrating.