Nausea and vomiting. Constant pain in the back and abdomen can cause nausea. This queasiness may be constant, or it may come in waves along with the intense throbbing pain. Either way, the nausea may cause vomiting. If the vomiting is frequent, it can cause a lot of other problems like dehydration, electrolyte imbalances, esophageal erosion and nutrient deficiencies. The abdominal muscle spasms that sometimes accompany vomiting can worsen irritation in the urinary tract and cause the pain to worsen.