What Could Sore And Foul Smelling Vaginal Discharge Suggest?

for about five months now i've been having the weirdest things happening. sometimes it itches and sometimes its sore. but now i just have a clear discharge with a foul order i think is coming from my clitoris. i've been to my doctor and he's ran every std test and infection test you can think of and everything comes back negative. but yet i still have a foul odor and i've never had this before what's wrong with me