Why does the back of my leg hurt when i walk for about 20 minutes?

Pain in the back of your leg while walking for about 20 minutes could be due to several factors, including muscle strain, tightness, or overuse. Conditions like hamstring strain or sciatica may also contribute to discomfort. Additionally, issues with your gait or footwear could exacerbate the pain. If the pain persists, it's advisable to consult a healthcare professional for a proper diagnosis and treatment plan.