I Have Pain In My Lower Leg. It Is In

I have pain in my lower leg. It is in the back part of the leg that radiates up to part of the thigh and down to part of the calf. There is no pain in the knee. When im sitting its like an aching pain when i walk or stand it feels like a tugging or pulling type of pain. It has gotten worse over the past week. No change in activities. No warmth, redness, or SOB.