After my workout why my blood pressure up very high.?

May be normal. Elevated blood pressure after exercise is the normal physiologic response to exercise. The top number (systolic) especially rises, and the bottom (diastolic) number tends to actually get lower with better conditioning. The better condition one is in, the faster the BP returns to normal, and the baseline BP tends to be lower. Rarely, the BP response may be excessively elevated and dangerous.