Undiagnosed Severe Left Flank Pain For Months - Kidney Related?

I have had severe left flank pain for 3 months now and still not been able to get a diagnosis. I am a 24 year old usually fit female.

The pain started towards the end of April while i was in work (an office desk job). It was on my left side in between my hip and ribs, spreading down to my groin. The pain got worse over the next couple of hours, and it has been a constant dull ache since then. The pain is most strong on the back of my left side but i can also feel it from the front.

I went to the doctors with this pain where i done blood and urine tests and got put on antibiotics for a suspected kidney infection, as well as codeine to ease the pain. The results came back with an apparent slight kidney abnormality showing, but a week later, i was still in a lot of pain and unable to move much, so i went back to the doctors where i got referred into hospital. I spent the night in hospital where i had more blood and urine tests, as well as an ultra sound. The hospital told me my results showed a UTI, but the ultrasound was clear, so i got put on another course of antibiotics and sent home. A week later, i was still in a lot of pain so i went back to the doctors where i was put on another (stronger) course of antibiotics for 2 weeks. The pain eased slightly above the groin, but the main pain on my left side was still the same.

My doctor then referred me to gastroenterology at the hospital where i had to wait weeks for an appointment, only to be told that he didn't think it was bowel or stomach related (as i can still eat and pass stools normally) and that i should have been referred to urology.

My doctor referred me to urology where the waiting list was 2 months, so i decided to get a private consultation with a urologist. The consultant done a urine test, which confirmed i had blood present in it. He went over my symptoms and suggested a CT scan in case i had a small kidney stone stuck which had been missed by the ultrasound. He was also concerned at my frequency as passing urine (this is usually over 20 times a day with anywhere between 3 to 8 times through the night). He referred me back to the NHS for the CT scan which i had a few weeks ago.

The CT scan results came back clear of kidney stones. My consultant now thinks the issue could be musculoskeletal but he still wants to see me to do some bladder studies as he is concerned about the frequency of urination. I have an appointment with my urology consultant for a few weeks time, but to see someone to investigate if the pain could be musculoskeletal there is a 3 month waiting list.

I am still in a lot of pain, both when moving and sitting (it never eases), and it is effecting my every day life. I can't go into the office to work due to the amount of pain i am in, i can't drive with it, and i haven't left the house the past few month apart from doctor or hospital visits. I am constantly feeling down and tired, and often get spells of dizziness and my eyes blacking out when i stand up (i am unsure if the tiredness and dizziness is related or not). I had a breakdown the other weekend where i cried for 2 days straight with the pain, the frustration of not being able to get a diagnosis, and not being able to do anything. I am worried that depression is kicking in with how long this has dragged on for.

I had no injury or knock to the area before the pain started. My mums side of the family also has a history of nephritis (kidney disease) with 4 of my aunt and uncles having it, but my urology consultant doesn't think there is a connection.

Is anyone able to provide any help or suggestions on what they think this pain could be as well as how to help ease it (the codeine doesn't help)? I feel like i have been passed around so many different people who still have no idea what is causing this pain.