I, too, have been battling this problem since last year. I find each bout is not as painful as the last, but the achiness afterwards persists for a long time. My last bout was several months ago and I still am not 100%.

Based on the information I have seen, it appears that epididymitis has many causes: cysts, bacterial infection, trauma, vasectomy (i.e. a blow out in the epididymis due to built up pressure), etc....

I agree that an in-depth survey might identify certain trends that could eventually identify the causes and lead to better treatment. What we need is more research. A lot more research! Doctor, how do we get the field of medicine (urologists, med students, etc...) to perform more studies? Is there any institution out there that comes close to specializing in this field?