Hello dear, The reason for your knee pain can be attributed to your obesity. Because of an increase in the body weight, there is increase load on the knees to support it, resulting in wear & tear. You need to follow a low fat diet & perform regular exercise to lose your weight. Investigations like lipid profile, estimation of blood sugar & blood pressure will be helpful. Also get an X ray of the knee & elbow joints done to rule out any pathological cause of pain like Osteoarthritis. Symptomatic relief can be obtained with application of analgesic+muscle relaxant gel & intake of calcium supplements to strengthen your bones. Wishing you a good health. Take care.