while usually just muscular soreness (possibly from doing something stupid while high), it can extend to common side effects such as bloodshot eyes and temporary memory loss if they're causing discomfort.
it can also apply to situations where pain is experienced while obtaining or preparing a joint, including cutting yourself by accident while chopping weed or getting a papercut from low quality rolling paper.
joint pain, although temporarily uncomfortable, is always worth the struggle.
jack: why is this joint blue?
brett: i had to use construction paper.
jack: so then what's with the red dots?
brett: joint pain.