Internal conflict describes troubles or disagreements which occur within an entity. Such conflict may occur within a single person, an organization, or even a nation. What makes internal conflict distinct is that the trouble is not necessarily instigated by or dependent upon an external factor.
For an example of single-person internal conflict, consider whether there has ever been a time in your life when you had a hard time making a decision. People face such situations all the time, but some decisions are harder to make than others. Think about some of the risks that can come with medication, especially for serious illness. Many people who have cancer struggle to decide what kind of treatment to receive, if any. On one hand, cancer may kill the sick person. On the other hand, chemotherapy is incredibly stressful on the body and mind. People facing internal conflict may feel as though they must choose the lesser of two evils, or the option which might cause the least suffering for themselves or others.
Intra-group conflict on a small to medium scale may or may not be more difficult to work out. In group settings, there is usually the benefit of discussion, but the possibility that things may not turn out the way you wanted. Let's imagine a school activities group who are working to plan the next social dance. Half of the group think the dance should be a fundraiser to help purchase some new sports equipment for the school. The other half of the group want the dance to celebrate their friends who will be graduating. Both halves of the group may have good reasons for why the dance should be dedicated to a particular cause, but how do they decide which is better?
This leads me to our third level of internal conflict—that which occurs on a massive scale. I believe that the best solution to the types of conflict which occur on any group level (be it big or small) is to discuss the facts and opinions and take a vote among all members. As an example of a massive scale internal conflict, consider the tension that arises in a nation during election years. Nations may have many political parties with differing beliefs about how the government should carry out its duties. What's more, individual members of political parties have their own beliefs about how the government should operate. Conflict on such a large scale can sometimes escalate into violence, but ideally it is resolved through discussion and a "fair and square" vote.