A urine and sperm culture for pyogenic organisms and mycobacterium should be done for chronic testes pain. This should be able to point towards the chronic infection and give the guidelines for the further management. A prostatitis may cause testicular pain. Urine culture after the prostate massage and semen culture would be helpful in diagnosing the chronic prostatitis.
Following other causes to be considered for the pain are;
1) Recurrent torsion
2) Torsion or inflammation of the appendix of the testes
3) Infectious epididymitis
4) Noninfectious epididymitis; occur due to reflux of urine through the ejaculatory ducts and vas into the epididymis, producing a "chemical" inflammation
5) Referred pain - the genitofemoral, ilioinguinal, or posterior scrotal nerves CAN CAUSE REFERRED PAIN. Other causes of referred pain are abdominal aortic aneurysm, ureteric stone, lower lumbar or sacral nerve root impingement, retrocecal appendicitis, retroperitoneal tumor, etc.
6) Idiopathic cause; cause not ascertainable.
Thus, your testes pain should be reinvestigated. A urologist working in a academic center like hospital attached to a medical school would be the best to consult; for working up your symptoms. Please see the causes of testes pain this authentic resource;
Please feel free for your follow up questions.
I would be happy to assist you further, if you need any more information.