Like squeezing a golf ball through a straw

Gallstones - like squeezing a golf ball through a straw: "Picture trying to squeeze a golf ball through a straw - Those suffering from gallstones need not imagine it; they may experience it firsthand.

Certainly, not all gallstones are the size of a golf ball. They can be as small as a pea or a grain of sand. But whatever the girth, the result is the same: pain. "
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I can certainly relate to this.