Zegerid and Kidney Pain?

Hi,
I've recently started taking Zegerid and it seems to be making my kidneys hurt. The pain is in my lower chest, but in my back... where my kidneys are. It comes and goes. Does anyone else have this?
Also, I have shortness of breath. I've had a chest x-ray and full pulmonary test done and they found nothing wrong. I can't get a satisfying breath without yawning, or gulping in air. My normal breaths don't feel satisfying.
Oh, and they took an ultrasound of my heart for other reasons. So the chest pain (that I used to get really bad WITHOUT Zegerid) isn't from my heart. I have to make a note here that Zegerid has really really helped my GERD. I don't get terrible chest pain and burping like before.
What other tests should I ask my doctor to do, for my lungs or my kidneys? My doc seems to think this is all due to the fact that I have a little anxiety. But I know it's not that, because I don't feel anxious on an everyday basis. Only when flying or stressed.
Any advice?