Waking up with a lot of discomfort on both sides of your back after holding your urine in the morning may be related to urine reflux and urinary tract infections. Prolonged holding of urine causes an increase in urine in the bladder, bladder volume and bladder pressure. The bladder can remain under high pressure, causing urine to reflux from the bladder and ureters. Urine flows down the ureter and into the renal pelvis, which can lead to hydronephrosis, a condition in which the patient usually experiences back pain. There is also the problem of holding the urine for a long period of time, which results in the urine not being excreted in time. Bacteria in the urethra can easily grow and multiply, thus causing urinary tract infections, and patients may also have symptoms of lower back pain. There may be other reasons for the discomfort on both sides of the waist after waking up from holding in urine in the morning, so it is recommended to seek medical advice in time, follow the doctor’s instructions for relevant examinations, and deal with or treat the problem with the help of the doctor.