Tired, aching legs are very common, mostly in females and also in elderly people. The cause for tired, aching legs can occur for different reasons for different people and the symptoms can also differ on a case-by-case basis.
Typically, people suffer from a consistent dull ache at the back of the lower leg, often behind the knee or in the calf muscles. Aching legs are most prominent after standing for long periods of time. Women wearing high heels often complain about tired, aching legs.