I have the same issues. I was diagnosed with panic disorder 10 years ago, and get palpitations when I feel anxious. I also get this feeling like there is a bubble or a burp stuck in my chest. I've also seen a cardiologist and have had extensive blood work done. Everything came back fine, so I just try to work on my anxiety so that I don't feel this way. If all your tests came back fine, then you shouldn't have anything to worry about. Try doing some mindfulness and relaxation. I know that is easier said then done, but the more you practice, the easier it is to control your anxiety and the resulting symptoms.
You overcome this by overcoming your anxiety, mainly. If you have constant fear and are taking meds, the meds you're taking aren't the right ones, they aren't working. But truly, therapy is the way to ultimately fix this. Many do overcome specific physiological concerns by relaxation techniques, such as breathing exercises, meditation, and the like. Now, some of it might also be digestive in nature, a lot of anxiety sufferers also get digestive problems, and the meds we take for it can cause digestive problems as well. But as you describe it, it sounds like you have a common anxiety symptom of thinking things are happening that aren't and that you wouldn't notice at all if you weren't anxious.