First of all, many thanks to Iolite for providing so many suggestions and resources.

As noted below, I had an injury to my testicles some time ago. After what seemed to be a complete recovery, I now have recurring bouts of pain and swelling. Medical diagnosis has not found any problem to treat. This situation seems to be outside the "normal" range of testicle trauma: as I understand it, usually there is either a swift recovery over a few hours or days, followed maybe by a slower return to normal over a period of weeks, or else there has been serious damage done that requires early surgery. My repeated but isolated problems are both annoying and frightening.

At Iolite's suggestion I tried a castor oil pack, which I applied with heat for one hour a night for three nights. Today I am almost symptom-free. However, past episodes have lasted from one to five days, so I can't really say, so far, whether there was any real effect from the castor oil. But at least it feels good to be trying *some* kind of treatment.