Worried ovary cyst?

so i went to da E.R ... because i had pain in my right side on da lower part of my stomache and they tought it was the appendix. so they did X-ray and found out dat i have a cyst on my right ovary the doctor said it was very small and that very common in women. He said to go to my gyno and see what they say. . . But im kinda scared b-cuz i've heard a lot of people who have cyst can't have kids. does anyone know what is the cause of da cyst on da ovaries. i know it's fluid but its there any other causes for it.