Old English stingan "to stab, pierce, or prick with a point" (of weapons, insects, plants, etc.), from Proto-Germanic *stingan (source also of Old Norse stinga, Old High German stungen "to prick," Gothic us-stagg "to prick out," Old High German stanga, German stange "pole, perch," German stengel "stalk, stem"), perhaps from PIE *stengh-, nasalized form of root *stegh- "to stick, prick, sting."
Specialized to insects late 15c. Intransitive sense "be sharply painful" is from 1848. Slang meaning "to cheat, swindle" is from 1812. Old English past tense stang, past participle stungen; the past tense later leveled to stung.