High BP when I'm stressed out. My anger?

I am IT professional working 10 hours a day and some time 12 hours a day, my blood pressure looks normal 123/85 during day time but in the evening it increases and some times when I'm stressed out I start feeling butterfly feel on mid of chest and when I check my BP it almost touch 170/110 but once I realize that start taking deep breath and when I check again it comes down slowly and it takes 10 to 15 minutes to come back to 130/100. Kindly let me know why my bp goes very high when I feel stressed out, is that some thing I need to worry ? Also how can I handle my stress and control my anger ? I have a BP machine so above mentioned readings are taken at home by myself. Also I'm person who go for regular master health check up every year so far no issues found on my ECG and ECHO test. Thanks