Ease my pain

I have been diagnosed with BPH (2006) and treated with Flomax,  Terazosin, and Nortryptyline, but have not achieved relief from pain nor from urination frequency (6 to 12 daily - 3 to 6 nightly).  Family physician and urologist are perplexed.  Gastroenterologist has done colonoscopy and found only minor diverticula.  Pain is periodic:  daily pain-free mornings,  pain starts around 3 pm and continues to bedtime, easing somewhat late in evening. Pain located in rectum, urethra, and sometimes in low pelvic area.  Some days pain is debilitating, unable to bend or walk, but next morning OK.  Was relatively pain free for 6 weeks last fall, and for 8 weeks this past Feb & Mar.  Low appetite, but I make sure I eat well,  but I have lost weight (160 to 154 lbs).  My and my wife's retirement years are on hold while this daily recurring pain persists.  Please help!