Can Ovarian Cyst Drain/resolve By Its Own?

I have a complex cyst 3.6 cm in my right ovary and polycystic changes were seen in my left ovary. doctor advised ovral l for 21 days. pain is persisting in my right side lower abdomen since my 4 day of periods. is there any chance that the cyst drain/ resolve by its own. or do i need to undergo a surgery. My Ca125 test is positive, value is 95. please suggest