Next time you do your back workout try and change things up in a unique way. Instead of doing your normal routine and exercises try doing chinups and pullups with an uneven grip. By placing your hands asymmetrically you will stimulate more fibers and create a new stimulus for your body. Try and find a pullup/chinup bar that has multiple handles. You can try the following :
1. Pronated/supinated alternate- Place one hand with your palm facing you and the other hand with your palm facing away from you. The palm away grip will put more tension on your back and the palm facing grip will stress your biceps more.
2. Neutral/pronated- Place one hand facing away from you and the other in a neutral grip. This will stimulate the outer head of the bicep and hit a different angle of the back.
3. Vary grip distance- try and place one hand wide and the other not as wide on the other side of the bar.
*** Just remember in order to keep your body even, make sure you do the same amount of reps on one side as you do the other.