Hi I see that you relisted the question.
I understand your frustation and I am trying to help you with the information you have provided me.
In sum- kidney pathology will not cause lower back pain unless you have infection or polycystic kidney disease. You need a kidney ultrasound.
Other causes for lower back pain would be GI- you need to consider reflux and gallbladder disease
Finally, you need to consider musculo-skeletal causes like herniated disc, nerve compression, etc. - which is why I asked you what you did for work and if you have pain radiating down the legs (less likely)
Since you are female, gynceological pathology is also a possibility and getting an ultrasound of your pelvis to evaluate your ovaries and uterus is an important part of your work up.
This microscopic hematuria can be a complete red herring in regards ***** ***** cause of your back pain.
So- this is my advice
1. Try the antacids. No harm in trying, may make you feel better. Then your investigation is done.
2. Get a pelvic ultrasound to rule out pelvic pathology
3. Get an ultrasound of your gallbladder to rule out gallstones
4. You can consider getting a biopsy of the kidneys, but this is contraversial in patients who do not have signs of glomerular bleeding (red blood cell casts in the urine- would have been reported and you would have been told of this)
5. If all of these are negative, you can consider a MRI of the lumbar spine, but I don't think that this is the cause of your pain.
This is what I meant by broadening the net