Hi and welcome to HCM. These sensations are called palpitations. For most people, palpitations are a once-in-a-blue-moon occurrence. Others have dozens a day, some so strong that they feel like a heart attack. Most palpitations are caused by a harmless hiccup in the heart’s rhythm. A few reflect a problem in the heart or elsewhere in the body. Most of the time doctors relate it to anxiety, deppresion or some psychological problem. Although sometimes that’s exactly right, it’s important to first rule out harmful heart rhythms and other physical causes. I think your doctor has ruled out serious problems, so no need to worry now. Follow few of these advice 1. Avoid caffiene 2.Avoid smoking and alcohol 3.Avoid decongestant medications 4. Drink plenty of fluids and get adequate sleep 5.Practice meditation or yoga to relieve stress 6. Practice some breathing exercises. I think i answered your query, all the best. Regards