Meditations 7:64

For times when you feel pain:

See that it doesn't disgrace you, or degrade your intelligence—doesn't keep it from acting rationally or unselfishly.

And in most cases what Epicurus said should help: that pain is neither unbearable nor unending, as long as you keep in mind its limits and don't magnify them in your imagination.

And keep in mind too that pain often comes in disguise—as drowsiness, fever, loss of appetite. . . . When you're bothered by things like that, remind yourself: "I'm giving in to pain."