Often, people who bang out a lot of chinups in their LP will progress until they experience elbow pain. You don't mention pain but still, it's possible you just did too many, too often and too bangy.
Stop doing them for a while. Like months. Do bent over rows or seated wide grip pull downs or any other accessory that will work your lats. There's no prize for getting the most chinups and it is not in itself an important enough exercise to stress over like you might do with a squat or deadlift issue.