Anal spasms. I m having that burning!

Hello I have been having Anal spasms since mid aug after I came back from traveling It's so much burning and paining inside the anus, i recently visited a colorectal surgeon, he gave me nifadepine 0.2 percent ointment, i started having pelvic floor exercise for a week in the first week of sep and it burning stopped and pain too, after i came from doc visit after few days again it got started and i kept doing exercise and it got fine and I m applying the ointment also twice outside the anus as doc advised me to do outside, but again since 3 days I m having so much burning sensation and pain inside the anus , i have a history of anal fissure so when i had went for travelling I got constipation and after coming back it stayed for few days as I have ibs-c I think because my constipation comes and goes even i don't eat outside still it comes, fiber cause more constipation to me I don't know what should I do for this anal spasms, if the stool is normal still i m having that burning