Hello there I have read through your question and would like to tell you that chronic constipation happen s because of a faulty diet and drinking less water. Taking too much of processed foods like cheeze, refined flour in diet can lead to constipation. Straining too much while passing stool can lead to hemorrhoid s , fissure and fistula in ano. The pain you are describing is consistent with fissure. I would advise you to visit a surgeon for proper clinical examination. Meanwhile you should follow- 1. Drink atleast 4-5 litres of water daily. 2. Include a lot of fibres in your diet like spinach, carrots and legumes. 3. Avoid processed foods. 4. You can use a steroid cream like anovate to relieve pain. Hope that answers your question. If you have any further questions please feel free to write. Thank you for choosing healthcare magic.