Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice.

The most dreaded cause for pain in testis in an adolescent male is Torsion of testis, which means the testis rotates or twists on its own axis (like the pendulum inside the bell). It is at risk to lose its blood supply if such an unfortunate event occurs. And the golden period before it could be saved is just 6 hours. Means within six hours, surgery has to be done to correct the problem and save the testicle. Your grandson's pain is not typical of this dreaded problem. But there is a clinical variant called intermittent Torsion which can cause pain on and off. The examination done in the normal period is generally unremarkable. A doppler study of testis during such painful episode may help. Nevertheless, it's advisable to rush to a nearby hospital whenever he develops acute pain.

Hope I have answered your query. Let me know if I can assist you further.