Testicle torsion usually occurs on one side only.
Prompt treatment is necessary to salvage the affected testicle.
Swelling, redness and tenderness of the scrotum. Nausea and vomiting. Rapid heartbeat, if pain is severe. It is occasionally present at birth, or may rarely be caused by an injury or sudden, forceful contraction of muscles attached to the testicle and spermatic cord. Your own observation of symptoms.