Can my blood pressure be pretty high one day, fine the next for some reason? Doc gave me atenalol but I only had one episode does this me I have hbp?

Many variable. BP is a dynamic measurement: it's always changing. It's not unusual for people to have periods of higher or lower bp. It's the average, taken at complete rest over weeks to months that determines if you have hbp or if you do, if it's well controlled. If you're in pain or have a separate illness, don't measure your BP then as an elevation will not mean anything (it's expected) .