Posting on behalf of a friend who isnt on Mn.
She has been experiencing this sensation at night for a while.
When she is asleep and breathing more deeply, she is experiencing a pain around her waist as if the waistband on her pj's are too tight. It happens when she pulls them down below her belly before she goes to sleep too. So its not that.
If its relevant, shes F 46 Im guessing around 3 stone overweight, but is dieting and exercising, and has lost a good deal of weight this year.
Non smoker but vaper.
Tia