Lying on your belly wouldn't hav done any harm, you'd have just turned over in your sleep if it was causing any problems
As for the pulling pain down below... is it sor of in your groin area? How the pain in your hip too? I hate to say it, but this is how I start with SPD. A really 'heavy' sort of feeling down below, lower back pain, and burning hips. Sorry

It may be not, but I thought I should say
