Normal heart echo kidney blood work and kidney doppler still have high bp sometimes a day like 145/82 i am 18 ?

BP readings variable: BP normally tends to vary depending on the state of your mind and your body. So you need to check it when you are at rest and mentally calm and relaxed. It is this reading which guides doctors how to manage and when to medicate you for "high BP" Your BP at rest should be between 110 to 130 systolic. If it is going up into 140 range, then your doctor needs to check and treat your BP.

Hypertension: Have you been pregnant? have you had h/o hypertension during pregnancy? Also there are w/u for endocrinological reasons need to be done based on the clinical situation. If everything is ok, it is called idiopathic hypertension, that means no identifiable cause.