I'm a healthy 43y m, suffering from urethritis and epididymitis for 2 mths now. symptoms, burning when urinating, urgency to urinate and pain in testicles & groin. std tests have returned negative. received nitrofuran, cipro & minocycline. no help?

It is likely you have neither condition. Urethritis and epididymitis do not fit well with the symptoms you describe; they are more typical for things like interstitial cystitis, prostatitis, or chronic pelvic pain syndrome (CPPS). (Google it for more info; the Wikipedia article is good.) With no help from these antibiotics, almost certainly no bacterial infection. See a urologist if not yet done.