I have a lump/swelling inside my vagina directly below my urethra? it blocks entire vaginal opening its so swollen, and its painful.

Ouch: That sounds painful. The most common lesion like this in the vagina is going to be a Bartholin's gland cyst, if it's really big, then it could definitely extend up as high as you describe. I would see a doctor or clinic asap and they can possibly drain this for you and relieve the pain that you are feeling. Regardless, an exam is warranted. Hope you feel better soon!