How long does after a bone marrow biopsy does hurt it for?

Not long. See my previous answer. Usually a day or so unless there were complications. If longer than a couple of day, i would call the doctor and discuss. There could be bleeding at the site with a hematoma or potentially an infection. A bruise is to be expected and can cause some soreness.
6-8 weeks. These usually take as long to heal as a fracture which is 6-8 weeks but the intense pain is decreased after about a week.