It's a sonogram, but they insert an ultrasound probe into your vagina for better imaging. I had several...they told me it would be just like a tampon (yeah right, a tampon the size of a football) I don't want to scare you. It really is the best way for them to get the images if cysts are the culprit. Definitely talk to your gyno about it. While most cysts are mild and harmless, some can be dangerous and you could also have something else going on...