Hi ragini and hope you'll find some good advice here. You'll definitely find understanding and compassion towards your physical and emotional pain.
What kind of surgery did you have for the fissure? Botox, lis, dilation? No matter which though, you are only 3 days out of surgery and pain and/or discomfort is to be 100% expected.
You need to continue to ensure your bm's are smooth, by whatever means work for you. Be sure to drink plenty of water and soak in hot baths as much as you can right now. Keeping that area clean is essential to prevent any infection
and the baths also help with the necessary blood flow that you need for healing.
If you are in need of pain meds to help you through, that would be a good idea...keeping the level of pain down will lessen your stress which is detrimental when trying to heal.
Best wishes for better days and full healing.
Angel