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.
Neurodegenerative disorders, such as Parkinson disease and dementia, are commonly associated with sleep disturbance. Medications such as steroids, bronchodilators, and some antidepressants can cause insomnia, so taking a careful drug history from the patient is important.