I use to have cancer cells i'm my uterus but had them froze off. a recent ct scan showed a mass between my ovaries and uterus. what could this be?

Mass on CT: There are many entities that appear as a mass, and the CT is only for identifying that "something" is there. Depending on its presentation, and your age, it could be many things. The fact that a CT was ordered indicates there is a suspicion that further investigation needs to be done. Work with your OBGYN/surgeon to determine the next step

Hard to say: It is hard to say what it is with limited information, usually a CT scan is insufficient to fully evaluate these types of abnormalities. It could be something as benign as a pedunculated fibroid, or it could be more serious. Speak with your doctor. Additional imaging with ultrasound and/or MRI may shed some light on what this might be.