Palpitations. These are caused by many things. Stress, excitement, irritants both physical and chemical, pressure like a hiatal hernia or esophageal push or pull, and primary heart things, the causes are very many in number.
Many things. Palpitations are a sensation of skipped heart beats. They can happen due to an electrical problem, a metabolic problem like thyroid disease, or may be the way you manifest stress. Talk to your doctor today for more of a workup.