I have a constant pain on my ankle/foot it has fluid on it all the time what could this be?

i have had pain in my ankle and foot for about six months now, it gets painful if i stand for long peroids ftimes if i drive for a long time when i dance or walk.... it looks to have fluid onit as theres a lump n feels like its got tissue or somethin init and the pain travels up to my knee. i had x rays done but the doctor didnt seem concerned about when she referred me. my blood test results came back that i was anemic so i was wondering what it could be.