Dear Rabbi, I heard that Chametz represent Yetzer Hara. If thats the case, why dont we eat Matza all days of the year? Thank you for your time

Your question is addressed in the Zohar (vol. 2. 183;B). The idea is that after the ill person eats Matzah the "healing food" which represents the Yetzer Tov for seven days, from that point and onward he can eat whatever he desires and it will not be able to harm him.