A knee that is painful and uncomfortable while performing activities like standing, running, walking, bending etc. is termed as sore knee.
Causes:
It can occur due to various reasons like a direct hit on the knee, infection, overuse of the joint, malalignment of the bones, or weak or unbalanced thigh muscles
Symptoms:
Knee can be painful in front, behind or around the knee-cap specifically while bending it for walking, kneeling, running or even getting up