There’s something called testicular torsion, which basically means a testicle has twisted on itself. It’s a medical emergency because the blood supply is cut off from the testicle, and for this reason it needs to be seen right away. 

What to look out for?

• Severe testicle pain

• Sudden testicle pain

• Swelling of one testicle 

• Tenderness of one testicle

And when in doubt, it’s always best to have it checked out.