Knee pain is very common, and often associated with activities at home or outside.
Got some young kids that you have to pick up after but it hurts your knee to bend down? Most likely your hip and knee are both tight.
Stand up, swing your right knee up in front of you with your knee bent, and then rotate your hip so that your knee points out to the right side of your body. Then start dropping the knee so it swings back in toward your body, so you are effectively drawing big circles with your knee. Repeat 10 times on both sides, this will loosen your hip and help your knee move more easily.