All young ovaries contain follicles, which are effectively very small “cysts” of fluid.
Sometimes these follicles can grow and cause larger cysts to form. Often, if the cyst only contains fluid it will resolve by itself but other times it continues to enlarge and needs to be removed. Large cysts can rupture or twist on themselves causing severe pain which is the reason they are usually electively removed with “key-hole” surgery.
There are many other types of cysts. Blood filled cysts are very common and can be very painful. Endometriomas are cysts associated with the condition of endometriosis and are also filled with old blood. Dermoid cysts may be filled with fatty tissue / hair or teeth! Occasionally cysts are sinister and need to be removed quickly.
Your doctor will carefully assess what type of cysts you have. A specialist ultrasound may be required. A laparoscopy (keyhole surgery) may be organised to remove the cyst.