I'm 28 years old and 10 weeks pregnant and i'm taking susten vt tablet for the past 40 days. now i have vaginal swelling and pain. is it normal?

No - get checked out: You should get examined by your ob/gyn to make sure there's no infection or anything like that.

See a doctor: pain is your body's way of telling you that something is wrong, I would definitely see your OB provider soon to figure out what's going on. you may have a vaginal infection, however it's unlikely to have anything to do with your vitamin intake.