You have not mentioned what type of scan shows such findings. Nevertheless, since ovaries are commented upon and a shadow is mentioned, I can only presume that it is an abdominal ultrasound. Among the pitfalls of abdominal ultrasound, a very common one is gas shadows from intestine covering important structures. It makes the structure, such as ovary, completely invisible. That is why radiologist ask to keep the bladder full before looking at the ovaries since a full bladder moves the intestines away. If it is a bowel shadow your radiologist talked about then all you need is a repeat scan with fuller bladder. I am sure this time both the ovaries will be seen. There are other possibilities like calcium deposits but these are very uncommon. So please get the scan repeated after some time. Ovarian pathologies may cause pain in the lower part of stomach (abdomen). So it needs evaluation. Have a nice day!