If you imagine your heart as a pump, which it is, the amount of force required will depend on your veins to transfer the blood to the organs or extremities. If these are clogged or too narrow more pressure is needed so a higher reading. There are 2 readings systolic and distolic and the average at rest is 120/80 for a normal individual. High blood pressure is called hypertension. There are many high blood pressure tablets and it is well known that snooker players take them to relax at the table. It is directed that once they are taken you will probably have to take them for the rest of your life so try to cure any underlying problem before taking them. ie too much salt,obesity, exercise, undue worry or what seems to be in your case hereditary. What extra can be done: some people swear by vitamen E capsules and various books have been written on its benefits. Others say Yoga is very relaxing. Trying to tell someone not to worry has precisely the opposite affect. I believe in the CT body scans which are quite affordable now:
http://www.lifescanuk.org
This will give you peace of mind.