There may be swelling in and around the quadriceps tendon. It may be tender or very sensitive to touch. You may feel a sense of warmth or burning pain. The pain can be mild or in some cases the pain can be severe enough to keep the runner from running or other athletes from participating in their sport. Stiffness of the knee is common when you first get up in the morning (or after a long period of rest or inactivity), and during and after exercise.