Osteoarthritis may be the cause of your pain
Your joint pain may not be caused by sports, but by osteoarthritis: a disease of the joints resulting from chronic deterioration of the cartilage. This condition also affects all joints, ligaments, bones, muscles and synovial fluid. While some violent or endurance sports can cause abnormal wear and tear leading to osteoarthritis, physical activity as such is not harmful, quite the opposite.

Movement is indeed beneficial for the health of cartilage. It helps maintain the flexibility of the joints, strengthen the muscles that support them and relieve pain by releasing endorphins. Large, multi-year studies have shown that running, for less than 30 kilometres a week, is good for the cartilage.
Unlike muscles and tissues, cartilage is not irrigated by blood vessels. It feeds on the nutrients found in the synovial fluid: a natural lubricant that also has the role of preventing cartilage deterioration. So, each time the joints are used, the synovial fluid enters the cartilage. Movement therefore contributes to the nourishment and lubrication of the cartilage.
However, with age, our body produces less and less collagen, which is a protein present in a large part of our cartilage and ligaments. Aging also has the effect of reducing synovial fluid content of glucosamine and chondroitin, two compounds that help slow cartilage deterioration.