What Causes Swelling And Hardness Of Urethra Leading To Severe Pain?

Hi my urethra is swollen and hard. I am a female and i noticed about a week ago at first i just woke up and need a wee and it was like somebody was stabbing it as i peed, it stopped hurting when going to the toilet but iv just looked at it and it is now alot more swollen and hard. It hurts abit when i sit down and i can tell its swollen when im walking around. Do you know what could be the problem?