Possible reasons of flank pain. At once?

It started with when I morning I used to get up mild flank pain randomly on both sides. Then become twice a day. I have realised while my usd and ct. Both the days when I had excess water for test. Intensity and frequency of flank pain increased. Now flank pain is not there but whenever I walk it pains on waist line in back left middle right, and when I drink water sometimes on waist line front.. Can only kidney stone be the only reason? If yes then my only question is why I get flank pain when I drink plenty of water at once? Whenever I walk a bit then on waist lines. Whenever I am sitting and had water front waist line. Apart from that I feel slight feverish all the time from inside not outside (dark red lips and hot mouth), Sometimes feeling of unwell.. Now a days I have realized no matter how much water I drink my urine never turn crystal clear like it used to before. I used to have one habit of drinking 1.25 ltrs at one go daily once in morning at 12 PM.