il c,

they inject dye into your uterus through your Hoo-haa to see if there is any tubal blockages, so the dye should come out the other end of the tubes near your ovaries.
not very painful, more just uncomfortable. i think it helps clear them out too. i had mine in August started clomid and concieved in both times straight after.

HTH

PS- everything crossed for you sarah(s).