I got shingles from a roof

Let's talk about shingles, or as I like to refer to them, spinal herpes.  

Shingles, the disease, is a viral infection also known as herpes zoster (more on that in a minute).  It's caused by the same virus that causes chicken pox.  I have had it, and it wasn't painful, but it itched like crazy.  Many people, especially older people, report that it hurts.  Most commonly, shingles presents as a rash that develops as a stripe of blisters that wraps around either the left or right side of your torso.

It's this wrap-around feature that gives us its name.  The word shingles comes from from Medieval Latin cingulus, a loan-translation of Greek zoster which means "girdle."  This ultimately derives from the Latin cingulum "girdle," due to how the disease wraps like a girdle around your midsection.

The rooftop shingle comes from the Latin scindula which derives from a root meaning splinter, or tear off, because shingles are just pieces that tear off from a roof.  The fact that the two meanings diverged into one English word is just an unfortunate coincidence.