Hi, Thanks for writing to HCM. Pain in the calf and difficulty in walking are experienced due to accumulation of lactic acid, decreased levels of calcium and electrolyte imbalance. Kindly take the following measures to overcome it: 1. Apply ice packs on the calf muscles after going for long walk. 2. Drink oral re-hydration solution regularly to maintain your electrolyte levels. 3. Drink good quantity of water, citrus fruit juices and tender coconut to keep yourself well hydrated. 4. Apply analgesic gel with mild massage on the calf muscles at night time. 5. Take calcium supplement tablets once a day for 15 days. You should see improvement in your condition by a week. Hope the information provided would be helpful. All the best.