your age is not much.. but if you are obese than pain in knees is common.. as obesity increases excessive load on knees.. which cause arthritis.. I don't know. what is your weight.. but if you are over weight than try to modify your lifestyle, avoid junk food, eat healthy and fibrous diet, intake omega 3fatty acids, calcium, do exercise and do cold compression early morning as first thing at the time you wake up and then go other daily activities, do some knee exercises.. don't do in exccess..do it in your comfort zone.. and under doctor advise.. they will tel you how to do exercise