What Causes Polyp In Vagina?

i've seen a doctor for 2 consecutive months coz i really bothered on those "small things" in my vagina. At first thet doctor told me its vagina warts, he do papsmear and prescribed me to put Aldara cream in order to rid off thos small things.. after 18 weeks of putting the cream, I went to see doctor again for some transvigal test which results to normal. And then, doctor do a so called minor surgery as he took out the polyp in my vagina and i had a little bit of bleeding and pain.. (is it dangerous? what is the caused of polyp?)