Mild pain in the right leg, more localized behind the knee, sometimes in the hip and ankle. not intense, no swelling or redness. started 3days ago.

Leg pain: Pain or dull ache involving the entire leg is suggestive of nerve impingement from a bulging disc or spur from a vertebra in the lower spine pressing on a nerve root. A knee injury or phlebitis would be more localized to the knee or calf. If discomfort persists consult a physician or a neurologist for diagnosis and treatment advice. An mri of the spine may be recommended.