Urological or kidney problem

Patient: My husband has had periods of severe pain in his lower pelvis. He says it feels like his scrotum is in a clamp. The GP said it is IBS, but the treatment did not bring much relief. A week ago, his urine turned very dark and he had very bad pain. The locum GP suspected kidney stones, and there was blood in the urine. Blood test did not reveal anything abnormal. Urispas has helped a lot for about 5 days, but since last night he has been in severe pain. His one kidney pipe was replaced with an artificail one more than 10 years ago and he has had kidney stones before. He is 47 years old, white male.