Knee pain is one of the most common reasons that keep people from doing the activities. Whether it is walking the dog, chasing the grandkids, going to the gym or just simply moving comfortably throughout the day, knee discomfort can hold you back. To find the solution to your knee pain, it is important to understand why your knee hurts in the first place. Here are 9 common reasons for knee pain, and some solutions to help keep you doing more of what you love.