"The acute pain that you may have felt immediately after the injury will decrease with time, but in the weeks after your fracture, some pain may continue and this is called sub-acute pain. This is mainly because the lack of movement that was necessary to help your bone heal has caused the soft tissue around the injury to stiffen and the muscles to weaken. In addition, scarring and ongoing inflammation may have developed in the soft tissue while the fracture was healing, which can also make movement difficult and cause pain."
From the article http://www.osteoporosis.ca/after-the-fracture/general-information-about-pain-after-a-fracture/