It may very well be that you have an infection, but there really is no evidence that chronic prostatitis is caused by a viral or bacteria infection. Some doctors are now even calling it chronic pelvic pain syndrome (CPPS) instead of chronic prostatitis, because they believe it is not caused by an infection.
I had prostatitis/CPPS for about 1.5 years straight when I was in my 20's. Several doctors insisted that it was an infection even though I wasn't even sexually active at that time. I was on hard core antibiotics for about 6 months until I started getting serious side effects, and they did nothing to help.
After a lot of research I found that there is a large number of men who suffer from this with no medical explanation. It turns out many people suffer these symptoms because of a muscle tension disorder that causes the pelvis muscles to tighten and spasm, which can cause all sorts of painful symptoms in the pelvic region including urethritis, swollen epididymis, testicular pain, among other symptoms.
I read a book call A Headache In The Pelvis http://www.biblio.com/book/headache-pelvis-new-understanding-treatment-prostatitis/d/883297827?aid=frg&utm_source=google&utm_medium=product&utm_campaign=feed-details&gclid=CPXB0ebc784CFQYdaQod0AMDDQ
Which shed a lot of light on the subject. many times CPPS is actually caused by stress and anxiety which can lead to pelvis spasms. The way I got it under control was through breathing exercises, stretching, and physical therapy. They also suggest something called prostate trigger release massage, but I didn't do that. It took me about 3 or four months to get it under control. Then I had flare ups for another couple years. Now I have no symptoms. Occasionally a little tightness which I can recognize now as early symptoms and get it under control quick.
I'd suggest checking out that book I linked if your prescribed medications aren't helping.
I haven't had problems for years, but was recently talking to an endocrinologist, and this topic came up. She suggested that it could have been hormonal too, because hormone changes in men can lead to similar symptoms.
Good luck.