Undiagnosed pain while urinating and abdominal pain

Hello,

I am 23, male.
My problem goes back a few months and is pretty strange so I will write from the time it started. It started off a few months ago (around February/March) while I was traveling, I would just have a burning sensation while I urinate, and maybe a bit afterwards that would last about 10-15 minutes after. I did not treat it as I was traveling, thinking it might be chlamydia (I had unprotected sex with a girl that had chlamydia, although I took azithromycin to clear it, hopefully. Did not check if I had it back then as I was traveling). About a month ago, I started having testicular pain as well. At first it wasn't too bad, but it got pretty excruciating soon afterward. I went to get a chlamydia test and got an antibiotic shot (to treat the seemingly epididmytis) and doxycycline right off the bat. Unfortunately, the test came out negative and the symptoms resided. I went to a urologist soon after, and got my testicles ultrasounded but there were no traces of epididmytis (this was about 3 days after I finished the doxycycline dosage). Also, I had a prostate exam that came out fine. The pain was still there with some random pain, mainly in the left side of my abdomen (about 3-4 inches below the belly button, more on the left side but on the right side as well). I got a urine sample that came out negative, also after being set in culture for 4 days. I was told by the urologist that I should try another kind of antibiotics, this time Levaquin. Even after the results came out negative, he said it was worth a shot. I still experience a burning sensation while I pee (it seems to be a bit better when I drink a lot of water but then I have to pee over 20 times a day. Right now I still go around 10 times a day which is more than I usually did). So now, my symptoms are a burning sensation when I pee, pretty annoying/sometime painful pressure and pain in mainly the left side of my lower abdomen (sometimes right), fever, and fatigue and tiredness a lot. I might have had this fever for a while but only noticed it lately, I'm pretty burning all the time but I always thought it was because of the weather, maybe, but that is just wishful thinking. Also, I do have a lower back pain history and it seems to be apparent more recently, although that might be unrelated as I didn't work out for a long time.
The situation is pretty depressing, especially since the urologist basically seems to be clueless as to the cause of this. If I mention any new symptom (notice the change in symptoms too. I'm glad my testicles aren't hurting, they occasionally do but I don't really take that as something unusual anymore) he says it might be now the colon, etc. Doesn't add up to the burning sensation (which might be a different thing altogether). I'm pretty tired of the situation and am about to move to a new apartment and start college, I don't suppose there's a quick fix but I would really appreciate your input. I was thinking this might be kidney or bladder stones or so, it doesn't seem to be an infection. I have also read an article where antibiotics can destroy the good bacteria in my kidney and leave the bad bacteria and that's why the lower abdomen is in pain now.

I would also add that I had unprotected sex with a girl that complains of UTI's, she says her doctors don't know what she has either (negative on STD's), but she is in pain during sex and occasionally peed blood, so I might've gotten whatever it is through her.
Thank you so much.