It could be a lot of things, not necessarily related to the bone.

What part of your leg hurts? Osteoarthritis primarily affects the joints.

Did you injure your leg recently? Do you do any work, sports or activites that cause you to make the same repeated movement with that part of the leg?

It is possible for people your age to develop osteoarthritis and it is increasingly common, mostly because of injuries.

But you should see your doctor and exactly describe the pain, where it is, what makes it feel better and what makes it worse. Your doctor may take an X-ray of the area to determine if the cartilage has thinned in the joint or if the bones show signs of wear and tear. Besides that, your doctor can help you figure out if the pain is due to osteoarthritis, a muscle strain, or some other cause.