HI Thanks for posting your query . I need to know your height and weight to determine how much over weight you are . You are gaining weight because your physical activity is not adequate enough to burn the amount the calories you consume every day . So each day that extra amount of calories is getting stored in your body as fat . Excess weight gain puts pressure on the legs , as they are the weight bearing parts of the body . So day by day the stress on your legs increases and you feel lot of ache in your legs ( especially at the end of the day ) Also added to that at your age there is a possibility of calcium/ Vitamin D deficiency which can make your bones ( including leg bones ) weaker and hence more strain on legs . So the solution is simple . Weight reduction . How? 1. Low calorie , low cholesterol diet : Avoid Sweet , Carbonated beverages , Non Veg food and fast food . 2. Aerobic Exercise : Do Brisk walking , Jogging ,Running on treadmill or cycling at least 30 minutes a day everyday . Also get your Serum Calcium and Vitamin D3 test done and revert back with reports. Any clarifications or doubts feel free to ask . Happy to answer. Regards ...