I’m sorry to hear that your knee is bothering you! Driving can certainly take a toll on the body, especially if you’re doing a lot of it. The most likely reason that your knee hurts from driving is poor posture and an unnatural driving position. However, you could also be suffering from osteoarthritis, which is caused by the gradual wearing down of the cartilage in your kneecaps.
If poor posture is to blame for your knee pain, here are some ways to improve it:
Consult your doctor before trying to fix the knee pain yourself, as the pain could be symptomatic of a greater issue—like osteoarthritis or even sciatica.