Is there any swelling of the leg?
Do you have any weakness of leg muscles?
Where exactly is the ache?
Have you seen a doctor? What did he say?
If the ache affects the entire length of the leg then that is different from a muscle problem affecting the thigh muscles.
You need to see a doctor for examination of muscle power, weakness and sensation to understand where the problem is originating. This may be a sign of reduced circulation so peripheral pulses should be assessed and a Doppler ultrasound considered.
I would also suggest blood test for anemia and thyroid function to rule out other causes of fatigue.
I would consider the use of ibuprofen 400mg three times a day when required, to see if that gives you any relief in the meantime.