The quick answer is “no.” Having low bone density in itself doesn’t hurt at all. However, here’s the catch: If your bones start to fracture because of low bone density or other factors, that can hurt plenty! Compression fractures in the vertebrae can be extremely painful and may even require surgical intervention to find relief.
Having said that, low bone density does not mean your bones are going to fracture. Bone strength results from a combination of factors, not just from bone density. It is possible to have low bone density and never experience a fracture, and it is also possible to have high bone density, yet have brittle bones that are prone to break. For more information on this topic, I recommend reading The Myth of Osteoporosis by Gillian Sanson. A review of this outstanding book is coming up soon on this website.