You need to be assessed by a physician right away. (Without more info hard to tell what may be going on...but epiditimytis and testicle torsion are always a concern)
Testicle pain is discomfort in one or both testicles. The pain sometimes radiates to the lower abdomen. Testicular pain can be due to injury, infection (Epididymitis or Orchitis) or inflammation, testicular torsion(most common in young men between 10 and 20 years old), excessive bicycle riding, hernia or kidney or ureteric stones.
The final diagnosis can only be made after a thorough physical examination including examination of the abdomen, scrotum, testicles and rectum.Pls consult a urologist for that.
Lab investigations like complete blood examination, urine examination, ultrasound lower abdomen and sometimes a urethral swab will help in diagnosis. Treatment will be started thereafter.Hernias are to be dealt surgically.
I hope that helps. Please do keep me posted on how you are doing or if you have any additional doubts.Warm regards.