Break and pause can cause problems in English because in Czech, you say the same phrase, „Dám si pauzu“ for both. In English, however, there is a bit of a difference.
A pause is shorter, usually, and it interrupts an activity for a short while, then the activity is resumed. The situation is the same, no major activity has taken place in the pause. So for example, you might take a pause when you are speaking, or you might pause the DVD to make a phone call and then a few moments later, start watching it again. It is momentary and the situation remains unchanged.
A break is where you stop an activity to do another one. So, for example, you might take a break for lunch, meaning to go somewhere else and eat lunch. It is longer than a simple pause. You might take a break in your studies to have a baby, or go travelling. You wouldn’t take a pause in your studies.