Gp says i have sinus tachychardia and its nothing to worry about. only fast heart. should i see a cardiologist just incase? maybe do a stress test?

Fast heart rate : It depends . Check your heart rate when you are we hydrated . Be sure to ask your GP if your blood count is normal and you are not anemic . Have your thyroid functions checked . If they are normal , then go see a cardiologist for a stress echo . If only for peace of mind . It will probably normal .

Depends on cause: once all the usual causes are ruled out , then a 48 hr holter should be placed to make sure there isnt a pattern to the rate that is missed,and make sure its not fast 24x7. A stress echo for structure, function, and to check for exercised induced arrythmias is reasonable