Welcome to HealthCareMagic. My name is Doctor Saleem Ur Rehman and I will answer your question.
I feel urged to congratulate you on facing your many ailments with a positive view and I hope you will continue doing the same whenever you face a problem.
You have a history of passing multiple stones since childhood which indicates that the problem may be long-lasting, even since birth (important risk factors include hypercalciuria: passing more calcium in urine, family history of kidney stones, and cystic kidney disease: fluid filled sacs are formed within the kidney).
Kidney stones can cause derangements in kidney function, thus causing an increase in
creatinine and a decreased GFR if they are located at he outlet of urine from kidneys. They can cause infection in kidneys if present for a long time.
Your flank and
back pain is consistent with kidney infection/stone. your
fatigue, nausea, loss of appetite are consistent with increased
creatine and urea in your blood due to either stones in kidneys or chronic inflammations.
If I were your doctor, I would have ordered an
ultrasound to look at your kidneys for any stones, or changes in their shape and size that might help me in ruling out kidney stones and
chronic kidney disease. I would have ordered a urine test to rule out infection of the kidneys. Then considering the results, I would either have started treating you or ordered further investigations like Xray KUB, CT scan, kidney biopsy etc.
As for your current test results your conditions seems to be mild to moderate. Creatinine is not raised much and the GFR is still far above the level recommended for
dialysis ( 10 - 15 ).
It can not be predicted at the moment whether your kidney problem is due to chronic stones or due to another pathology. It is, therefore, recommended that you make an appointment with your doctor for follow up and discuss this in detail with him. He will manage you the best.
Wishing you best of Luck.