Girls, has anyone had a cyst in the ovary? Today I saw a good experien…

Girls, has anyone had a cyst in the ovary? Today I saw a good experienced ultrasound technician. She said that there may be a cyst in the left ovary and come back for another ultrasound on the fifth day of the cycle. Then she will say for sure if it's a cyst or not. I just have occasional mild pain in the left lower side. I think it might really be a cyst. Has anyone encountered this? What should I do? If there is a cyst, how to treat it? Please tell me!