See a cardiologist. I don't anxiety would pop up only when you twist your torso. Also, if your GI doctor says have it checked -- it's worth it to check out. A clean bill of health will ease your mind, and in turn, your body.
I have that same noise when I do boxing/twisting moves. Unfortunately I don't know what causes it, and I highly doubt it's anxiety with me. I don't have any digestion issues. I have SVT and mitral valve prolapse, but that's it. I don't know if either of those could cause it. I'm curious to see if it still happens to me after the ablation, but it really doesn't get in the way of my everyday life. I have shortness of breath also, but I don't know if it's connected to the noise I hear when I do kick boxing type moves.