Knee pain after running, below knee cap and at the top of shin bone. Feels very sore and hurts, no swelling. Have iced and rest. What could it be?

Patellar tendinitis. You appear to be describing a classic case of patellar tendinitis. A common overuse type injury tht is almost always amenable to nonoperative treatment. Static quadriceps stretching usually helps resolve this complaint. Nsaids such as motrin, naproxen, or advil (ibuprofen) can also help. If no improvement after several weeks arrange for an evaluation by your physician.