What Causes Burning Sensation In The Anal Area?

Question : I have the Burning sensation in the anus from last 4-5 weeks. No blood, not other problem. I have been under a lot of stress due to my son's medical condition during that time. I went to my family physician and he told me with out examination that i might have initial condition of piles and he gave me a ointment sitcom and tablets for 30 days on April 29th . i had it for 10 days but no relief then i went to another physician who examined physically and told no piles but i might have fissure. so he prescribed me the crema gel ointment for 2 weeks. its already 7 days i dont have much relief but yes it has come down little bit. the burning sensation is there still. what should i do? I was detected with IBS last year but managing the things and no complications from that till now. i have got my gallbladder surgery done 3 years back due to the gallstones issue. since then off and on digestive issues are there of gas, bloating etc but manageable. i am worried about this burning thing as why is not getting cured?? i had anal fissure about 5 years back it got cured in about 4 weeks with ointment. Kindly suggest i am worried. How long the fissure might take to heal.