Although the word "karma" is Sanskrit and is associated with Eastern religions, it simply refers to the law of cause and effect. Karma is not blind destiny or divine judgment, but is the principle the describes the natural reverberation that emerges from every action, whether that action is physical, emotion, mental, or spiritual.
Suffering and pain are not punishment from a tyrant God, nor are they "normal" or mere "coincidence." When we truly understand the law of action and consequence, we can see that our lives are a result of our own moment to moment ignorance of the effects of our actions. We create our own suffering, therefore, we can create our own happiness instead, if we know how. No matter what religion or background we come from, through conscious action from moment to moment, we can originate a new set of causes, which in turn will generate a new set of results. This is how we can revolutionize our life. The power to change is in our hands.