When should i measure my blood pressure if i have only paroxistic high bp pheochromocytoma or paraganglioma? during an attack?

Anytime: If i understand you correctly, you have paroxysmal hypertension, pheochromocytoma or paraganglioma. The issue is not when to measure your BP but how to make the correct diagnosis. If you have a tumor causing your high BP then it needs to be identified, characterized and removed by a trained surgical oncologist or endocrine surgeon. If you have paroxysmal hypertension then you need a medical doctor.