Sore legs a few days after a colonoscopy biopsy are not directly related to each other, but may be related to excessive activity, varicose veins of the lower extremities, and lumbar disorders. 1. Too much activity: after colonoscopy biopsy, if you walk around too much, your muscles will produce lactic acid, and the accumulation of lactic acid will lead to leg pain and discomfort. 2. Varicose veins of the lower limbs: If varicose veins occur, it will affect the venous return of the lower limbs, and the blood will be stagnant in the varicose veins, and the patient will feel the pain and discomfort in the lower limbs. 3. Lumbar diseases: If the lumbar diseases, such as lumbar disc herniation, occur, when the disease attacks, due to nerve compression, it will lead to lower limb pain, often accompanied by numbness and other symptoms. It is recommended that patients go to the hospital, you need to do the relevant examination of the lower limbs, usually able to clarify the cause.