What Causes Ovarian Cyst?

yes me n my fiance have been trying to conceive for 3 or 4 months with no luck but that being said i have a cyst on one of my ovaries don't no what type had it for about 4 months haven't been to a doctor yet..i only know i have a cyst because i got a ct scan at the hospital after a car wreck and it showed up i was just wondering if that could affect me getting pregnant i also have an irregular period i have one every month just starts and end on different days...we really wont to conceive please help