I have a vaginal bacteria infection I get a lot of them recently sex has been hurting I stuck my finger inside myself and I felt huge knot what is i?

Vaginosis. You need to get evaluated as you do in fact have several symptoms of a vaginal infection. Painful intercourse (dyspareunia) is another sign of some underlying issue (possible infection). The "huge knot" you feeling could be reactive from your infection, like a vaginal abscess for example or a growing cyst, but an exam would be diagnostic. Best wishes.
See doctor. If at the opening may be a bartholin cyst but would need to be examined to. Tell what it is.