If you have had your heart checked, it's possibly just a harmless palpitation or nerve reaction. Does it happen when you have taken a cold medication? That can cause the feeling.
Yes, agree that this sounds like heart palpitations. https://www.mayoclinic.org/diseases-conditions/heart-palpitations/symptoms-causes/syc-20373196 For many, these are truly harmless as Anniebrooke says. Stress and exercise can bring them on. If you have any kind of chest pain, feel faint or anything like that, obviously see your doctor right away. If they keep up, you can talk to your doctor about it. Do you have an annual physical?