White coat syndrome as others have mentioned. I have this problem too (inherited from both sides of my family) and not a single doctor that I've seen pays attention when I tell them. Every year or so I spend a day or two testing myself at home and get normal readings but to them all that matters is the high systolic reading in the office. For some reason they find it inconceivable that an injured person who's in a building full of sick and dying people would exhibit an obvious symptom of stress like transient elevation of blood pressure ¯\_(ツ)_/¯
White coat syndrome, as the sibling poster noted. However, if you or your doctor aren't satisfied and worry about the high measurements in their office, you can ask for a 24 hour monitor - you take it home and it measures blood pressure regularly throughout the day (and unfortunately throughout the night too)
I get normal blood pressure readings at home but at the doctor it’s quite high. Is that pretty normal?