They do arise in the
joint , but may show up under the tendon sheath along a
finger. No, this is not an ER kind of thing. Tell your doc next visit. If it keeps you from full use of your hand be seen earlier. Treatments include letting them be, injecting them with steroids, and surfgical removal, but they can always return.
Old home remedy was to hit them hard with the Bible which would suddenly pop them, or, alternatively, to put the fear of God into them.