I'm Wondering If I'm Having Kidney Problems. My Urine Is

I'm wondering if I'm having kidney problems. My urine is very pale it comes out bubbly I also have pain in the middle of my back on the right side and my doctor did a drug test on me couple days ago because I'm prescribed pain medicine which is opiates for the pain in my body and it did not show up in the drug test. Could that be part of kidney problems?