My Husband Has Had Over The Past 2 Years Recurring

my husband has had over the past 2 years recurring pain in his abdomen and groin area , it comes and goes but is debilitating at times .then goes away for a month or two . we have been told once it was Epididymitis was treated but that did not stop it . i have been tested several times and was negitive . what else could it be , colitis or crones disease have similar symptoms , irritable bowel syndrome too . im worried but he says it will pass . are any of these life threatning ?