Pain in my left ovarie. All my test can back good no cyst like I thought. Ultra sound didn't show a cyst. What could it be?

Not ovary n. You can have adnexal pain unrelated to cysts. You can also have pain in your pelvis that is not gynecological in nature. Ask your doctor.
Ovulation. Ovulation mid cycle pain. May be caused by release of blood. The lining of the abdomen and pelvis the peritoneum very sensitive to even small quantities.