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.
Insomnia (say: in-sohm-nee-uh) is a sleep disorder. People who have insomnia may not be able to fall asleep. They may wake up during the night and not be able to fall back asleep, or they may wake up too early in the morning. Many people have insomnia. Chronic insomnia is when your sleeping problem lasts for 4 weeks or longer.