Hi, Thanks for writing in. The earliest sign of obstruction in the kidney is splitting of the pelvicalyceal system. This should further have an underlying cause. The cause can be a stone, acute infection or any scarring due to chronic infection and inflammation. It is important to know if there is any of the above mentioned conditions that might be causing you the pain. This may require further tests and evaluation by higher imaging methods. Please consult an urologist and discuss your clinical symptoms with the ultrasound findings. Drink adequate amounts of water and fluids.