Anyone ever deal with anal fissures?

Shortly after being floxed I developed an anal fissure from eating too much cheese. Well it went away after about a month and now it’s back. I had a cystoscopy done on my urethra and I clenched up so much during it that the anal fissure started hurting again. My doctor original prescribed nitroglycerin but it gave me a flare for my CPPS and then the other prescription Nifedipine/lidocaine compound flared my floxed tendons in my left thigh. I’m in a lot of pain and avoiding eating so I don’t make a bowel movement. Thanks.