Hi there and thank you for the question. I am a Registered Nurse and will be happy to help you today.
As long as you know you are not pregnant (verified by Dr exam and blood tests if you are sexually active), there are several things to consider. The area to the left and right of your belly button is the location for your colon. Intestinal gas moving through your colon can cause your stomach to feel like something is moving around inside of you. It could also be your pulse that you are feeling if you are thin.
Sometimes the abdominal aorta can bulge and even rupture. I think that since this is an ongoing event and not just a once or twice kind of thing, I would present to my PCP and have them do a physical exam on your abdomen to see if they hear/feel anything that warrants further investigation. A person does not always feel pain when they have an issue with their Abdominal Aorta but if there is something wrong, you do not want to hesitate. Not wanting to stress you out, just feel that after 2 weeks, you should at least get it checked out as soon as possible.