Pounding heart beat??

so i have jad thos problem for a while. my heart pounds when i walk up stairs or walk fast. or jump up fast... i do have bad axiety after having my son a year ago. i went to the doctors and they have done tests on my heart and everything isnormal. can anxiety cause ur heart to beat like this?? i dont really have panic attacks any more its just all around anxiety all the time. its stressing me out. please help! thanks