I Had A Horrible Sensation On My Clitoris, What Could It Be ?

I had a urine infection in the summer which had to be treated with two lots of antibiotics , afterward i still had some similar symptoms but was giving thrust treatment because tested again to see if the infection was still there came back negative, it didn t work so went to a GUM clinic to see if it was an STI however all the results were negative so i went back to the doctors and she keeps putting me on creams that aren t working, ive been examined and apparently it looks fine there but i still get this horrible sensation on my clitoris it mostly occurs after i whip there and is a sharp, pins and needles type of pain , rather uncomfortable. and i have noticed that after intercourse even though it doesn t look swollen, the lips feel like they are when you push down on them like the glands are sort of swallon, i am very worried about what this is and i m fed up of being given creams that don t work, any ideas of what the pain could be?