Why does my heart race sometimes i do have high blood pressure?

High Blood Pressure is often a result of your blood vessels not being elastic enough to stretch well. As the vessels harden, the heart has to pump harder to try and get the blood out to the extremities. Occasionally this overworking of the heart can cause arrhythmias (irregular rhythms). Talk to your Dr and ask for a referral to a cardiologist. They can do a holter monitor to see any arrhythmias

Not enough detail to to attempt to answer your question. If “heart racing”means episodic increase in the heart rate the cause could be exertion, anxiety, fear, fever etc. “Racing” may also be due to an abnormal heart rhythm which may subside on its own. Examination during an episode will confirm your impression and possibly lead to other tests to solve this problem. Please seek your doctor’s help.