I have bilateral flank pain. It started over a year ago. It will come and go. It starts as a dull ache, radiating into bilareal pelvis. It increases quickly from a dull ache to a sharp, throbbing pain. It will start, I medicate with 600 to 800mg of ibuprofen. Lately, I have to take 650MG of Tylenol WITH the ibuprofen to get it managable. These attacks will last 3 to 6 days and not happen again for one to two months. Each bout seems to be more intense.