As you doubts, cancer history in family can increase risk of ovarian cancer in family members. Moreover, cases of ovarian cancer develop usually after menopause. But it is not likely for you to have an ovarian cancer since your CT scan records did not show any abnormalities. Have a second opinion of your record from your doctor to get everything clear. Severe pain can also be a result of kidney stone. This pain is also called renal colic.
Good luck and get well soon.