I am also experiencing similar pain. I am 19 weeks pregnant and my belly button and the area right around my belly button hurt from time to time. It is sometimes constant but other days doesn't hurt much at all. I have been experiencing this for a couple weeks now.
The immune system is intricately connected to the hormonal system and the brain via messenger molecules, so that emotional stress and factors like insomnia have a great influence on its ability to function properly.
Secondary insomnia is the symptom or side effect of another problem. This type of insomnia often is a symptom of an emotional, neurological, or other medical or sleep disorder. Emotional disorders that can cause insomnia include depression, anxiety, and posttraumatic stress disorder.