For the last three months or so I've had daily bouts of heart palpitations, shortness?

of breath and some lightheadedness. My doctor had me walk a couple flights of stairs and my heart rate went into the 130's. He first had an EKG done and it was fine. Next was a chest x-ray looking for effusion or enlarged heart and that was negative. Then blood work to check my thyroid and electrolytes and they were fine too. So, he ordered an echocardiogram and Holter Monitor tests. According to the doctor, those also came back normal. I still have daily bouts of palpitations, SOB and some dizziness. Could this all be in my head? Can anxiety or other stresses actually control the body like that?