I have occasional knee pain that's even worse during the winter. I ran track for 4 years, but doctors found nothing wrong. Any suggestions?

Let me try to help. Most likely some arthritis early in type, some time dose not show on the x-ray, if you not be sure you request MRI to done that will show it.Good luck thank you.
Control symptoms. Your knee pain is either subtle arthritis or less often seen cause of pain that your doctor did not consider, such as iliotibial band syndr or pes anserine tendinitis. Your options are to seek a second opinion or use practical measures to control your pain. The options are ice, ibuprofen, tylenol, (acetaminophen) stretching, maybe a neoprene brace, and activity modification.