I have ovarian cyst the size is 5.5 4.5 what can i do? ?

Do not need to: Do much...It will likely resolve on its own. Cyusts greater than 5 cm may be at risk of casuing the over to twist on its blood supply cutting off circulation. If this were to happen you would know it becuase you would get fever/nausea/vomiting, severe stabbing pain on that side and then it would all of a sudden go away. This is called ovarian torsion as is rare. Again this will resolve on its own.

Ovarian cyst: It will probably go away on its own. Have another ultrasound in 3 months. Go to an emergency room if you get worsening pelvic pain as it could mean the cyst has burst or your ovary has twisted. Birth control pills help to prevent cysts but you don't have to take them if you don't want to. For sure follow up in 3 months with your physician.