Hi, Noted your history of lower back ache, bloating, had ultrasonography of abdomen, drinking a lot of water and so on. The back ache can be independent of the bloating in abdomen and both should be investigated separately. The commonest cause of pain on both sides of lower back are related to myalgia, fibromyalgia. Other problems that cause backache are spinal joint arthritis, prolapsed discs. This can be diagnosed by a clinical evaluation by an Orthopedic Surgeon, MRI of the affected area to know the exact diagnosis and thus get treated accordingly. Bloating can be as a reflex symptoms of severe backache due to aerophagia and then the abdominal other signs will be negative. But the causes of bloating in abdomen should be looked for before saying so. Get the X-ray of abdomen in standing position to see if there is any intestinal obstruction, Ultrasonography has already done, post the reports. Tests of stool, blood and urine; CT scan will further elaborate the cause if needed and the treatment will obviously be as per cause found. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. T. Chandrakant, General Surgeon