be a thorn in (someone's) side

To be a constant or persistent cause of annoyance, frustration, or trouble. My professor was an environmental activist when he was younger, and, apparently, he was quite a thorn in the oil companies' sides at the time.

Common Names:

Name	Pronounced	Usage
Ade	[eid]
DİDem	-	Turkish
Amosis	-	Ancient Egyptian (Hellenized)
Valencia	bah-LEN-thyah (Spanish), bah-LEN-syah (Latin American Spanish)	Spanish
India	IN-dee-ə	English
Bernetta	-	English