Normal back pain or kidney (?) pain

[WhenDoISleep]

I woke up on Saturday with a sharp constant pain in my back (left hand-side, at the base of my ribs). I have had niggles in my back before - all of which normally involved both sides of my lower back and resolved over a few days with OTC pain relief and gentle exercise (from the physio).

This has been nothing like that. Since Saturday the pain is constant and sharp. OTC pain relief plus heat has done nothing. There is no position I can sit or lie down in where it doesn't hurt and the last few nights I have had limited sleep as the pain seemed to get worse. Last night I was up from 2am due to the pain, there were definitely times when it was coming in waves. The pain is constant, but is not aggravated by e.g. bending or twisting. I was also v cold last night and have felt nauseous for the last few days.

I saw a GP this morning who prescribed stronger pain relief and was very keen to say it was normal back pain and to come back in a week if no better. I've taken the stronger pain relief but it has not killed the pain at all. I'm concerned from the NHS page that this might be kidney related. The GP this morning dismissed that as I don't have any UTI symptoms.

Based on people's experience does this sound like regular back pain or something that might be kidney related?