My bladder feels full and burns, urethra itches, tests all OK?

Last year I had unprotected sex and a few weeks later my testicles became sore. I went to the doctor and told my girlfriend and we both got put on anti biotics (they said it was probably chlamydia) The urgent care center lost my urine sample so I never got a confirmation on what i had. They gave me doxycylcine and the symptoms went away… for about 8 weeks. The urge to urinate frequently never really went away.

Then I began feeling a burning sensation in my bladder like a pocket of something stinging was in there. I went to another doctor they gave me a white blood cell test told me i didnt have an infection and sent me on my way.

months progress – THe burning sensation in my bladder comes back off and on – now with minor itching of my urethera and minor stinging. No discharge (ever)

Convinced I have something I go back to another doctor and they give me the same white blood cell test – they conclude I do not have an infection and send me on my way.

Now one year later I still have the same symptoms – slight burning in bladder (on and off) stinging when I pee (on and off) and the frequent urge to urinate. Except now, my kidneys have started to throb and sting. (left side then right side, sometimes my bad but the pain isnt consistant)

SO, i went to another doctor requested a full std test and urine test.

Neg to chlamydia, gonnorea, vaginosis, and even Myco Plasma Gennitallium.

The doctor looked at my kidneys from an ultra sound and said they look normal.

My doctor calls me and says there is nothing wrong with me. Fine.

WHY does my bladder feel full when it isnt, I have itching in my urethra and sometimes stinging when I pee, burning sensation in my bladder, and my kidneys still hurt on and off during the week. I now also get head aches constantly and some minor nausia (this never happened)

Could all of these doctors be missing something? Could I have a fungal infection? I promise I am not crazy and the symptoms I am feeling are real but no one is taking me seriously because the objective results on all of the tests.