Paget's disease of bone occurs when the breakdown of the old matrix and the new matrix speeds up; it can be up to 40 times as fast. This causes the bone to form differently so it is more vulnerable to fracture. The most affected areas are usually the pelvis, thigh bone(femur), lower spine, skull and shin bone(tibia).Nerves can become compressed because of the change in structure. The increase in activity also increases blood to the bone which can affect sensitivity of the nerves causing aching or pain.
Attribution: BUPA