Testicular pain can be due to infection (Epididymitis or Orchitis) or inflammation, excessive bicycle riding, hernia,varicocele,prostatitis or kidney or ureteric stones.
As there is no swelling or inflammation or redness of the scrotal sacs, so the chances of epidiymitis or orchitis are rare. In cases of hernia, a prominent bulge along with testicular pain is there and in cases of kidney or ureteric stones, pain during micturition may also be there.But most of them have been ruled out.I would suggest you to get evaluated for prostate causes.
Lab investigations like complete blood examination, urine examination, ultrasound lower abdomen,examination of the prostatic secretions and sometimes a urethral swab will help in diagnosis. Treatment will be started thereafter.My advise would be to consult a urologist.
Hope it helps.Take care and pls do keep me posted on how you are doing.Kind regards.