My blood pressure is sometime high but not every time is this normal?

Yes: BP varies throughout the day. Very high spikes without apparent reason may indicate underlying disease. If on average your blood pressure in the morning is greater than 140/90 you have hypertension and need evaluation. If you have known diabetes your BP should be less than 130/80.

Common, not normal.: Depending upon how high exactly your BP is, this may represent a problem that would benefit from treatment. Everyone experiences some fluctuation in BP during the day. For this reason it is sometimes useful to undergo a 2-hour blood pressure monitor to determine if the extent and duration of BP elevation warrant treatment.