If you had to wait for your doctor to "read the results" that is why it takes so long. But since your dad did it himself, he just told you what was going on.
You can see a cyst from a regular ultrasound, but you have to have the internal to measure it and try to determine what "kind" of cyst it is.
Anyway, yeah most women have cysts. They fill up and get bigger during the month and then on your period they go away, or at least shrink. That is perfectly normal. It is the really big ones, and the ones that do not go away that you have to be careful of.
Good luck dear, but if you keep having pain, you should really go to the doctor. Birth control is suppose help keep cysts under control. That is one of the main reasons I stay on the pill. I have a cyst on my right ovary.