I get occasional palpitations. I haven't had them in weeks, but having them now after drinking hot chocolate. I feel breathless. I usually only have them after being active. My heart beats normal and have normal blood pressure. What should I do?

Chocolate. Cocoa/chocolate can cause palpitations. Your symptoms suggest a rapid heart rhythm disorder (tachyarrhythmia). Ask your doctor for a 24 hour recorder (holter) or, if it happens less frequently, a 30 day event monitor to document what your heart is actually doing. Treatment hinges on this documentation. Get your thyroid and electrolytes checked. Avoid caffeine (coffee, cola, and chocolate).
Anxiety disorder. Coco has some elements of caffine. But if you have normal BP and hr, it's ok.
Palpitation Sx. Palpitations are an awareness of extra heartbeats which most of us have. The sensation can be single or multiple and can sometimes last minutes. Different people may feel other symptoms along with them such as dizzy, lightheaded or short of breath. The palpitations are almost always atrial or ventricular premature beats. Usually benign but they are also found with abnormal hearts.