Since the beginning of breakfast this morning, I have had an intermittent fluttery, pulsing movement/twitch just beneath the bottom of my ribcage, slightly to the left. There is no pain, only an uncomfortable sensation. Occasionally, I feel out of breath. This has been continuing for about an hour, now. My pulse seems to be steady and regular, as checked on my left wrist. I am a 50-year old white male, about 185lbs. so I m pretty sure I m not pregnant!
Thanks for your question on Chat Doctor. I can understand your concern. In my opinion, we should first rule out arrhythmia (rhythm disturbances in heart). Arrhythmia can cause Fluttering sensations, pulsation beneath left rib cage and mild breathing difficulty. And if not treated promptly, arrhythmia can be life-threatening. So consult cardiologist and get done 1. ECG 2. 2d echo 3. Holder monitoring (24 hours continuous recording of ECG). You may need anti arrhythmia Chat Doctor.  Don't worry, you will be alright. Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.