Since three months my urine is yellow in color. If I drink lot of water then it is coming normal. Morning again it is coming yellow. Taken 4 months, hiv,hbsag 3 months anti hcv non reactive. Taken urine test as well there were no infection in urine. I am getting scare please kindly tell what could be the reason. I have gall stones, Gerd. Left kidney shrunken 10 years back. Don't know whether it is working or not. But since 3 days getting left back pain. Vitamin d is low. Don't know about b12 my tongue got swollen since 3months same. Please help me out what could be the reason.