If the patient feels soreness in the lower back and left hip bone area, he/she can go to an orthopaedic clinic, which may be caused by a herniated lumbar disc, resulting in soreness due to compression of local nerves. If the soreness feels significant and unbearable, you can also visit the emergency department at night. However, emergency departments can usually only deal with emergencies on an urgent basis and are not able to perform systematic examinations and exhaustive treatment, so orthopaedics is recommended if available.