Josh has been experiencing excruciating pain ever since his bike accident. Though he had been successfully operated, he often complains of agonizing pain in his right shoulder. Karen, his girlfriend, tells him that he can harness the power of his mind to overcome pain by concentrating his thoughts on the pain—not by trying to avoid it. Karen is referring to:

Meditation

Explanation:

Based on the information provided within the question it can be said that in this scenario Karen is referring to Meditation. This is a very famous practice/technique, in which an individual tries to focus their mind on a very specific object/thought/activity in order to train their mind and body to achieve complete awareness and a calm and stable state. Which is what Josh needs since the pain he is feeling is all psychological, and clearing his mind will most likely relieve this pain that he is feeling.

yes, since there is a positive and a negetive if the positive and negitive wasn't there wouldn't a flow electricity in it.