If you have leg pain
then you have to rule out the casues for having leg pain. First of all check your weight and your haemoglobin levels, as Anaemia always leads to the symptoms of being tired and also having leg pain though there are no issues with the knee joint or back pain
. If not if the pain
radiates down the back of thigh and legs then it might be due to sciatica
. Kindly consult the nearby physiotherapist
. Hope you recover soon from the leg pain.