Sudden leg pain and soreness may be caused by physiological factors, acute injury, lumbar disc herniation and other factors. 1. Physiological factors: prolonged exercise or physical labor can lead to excessive production of metabolic products in the muscles and accumulation of lactic acid, which can cause sudden leg pain and soreness, which can be gradually relieved after sufficient rest. 2. Acute injury: Trauma can lead to damage to leg muscles, which can cause sudden symptoms of leg pain and leg soreness, accompanied by swelling and subcutaneous bruising, and in serious cases, it can lead to bone fracture, bone rubbing sound, pseudo joint deformity and impaired mobility and other clinical symptoms. 3. Lumbar intervertebral disc herniation: it may be related to acute trauma, lumbar degenerative changes and other factors. During acute attack, it will seriously compress the nerves innervating the lower limbs, causing sudden leg pain and leg soreness, accompanied by lumbar pain, numbness of the lower limbs and other symptoms. Sudden leg pain and leg acidity, and the symptoms are more serious, it is recommended that patients seek medical examination in a timely manner, to clarify the cause of the disease for standardized treatment, to avoid delaying the condition.