Have you explored diet? I suffered from anal fissures for many years. They cleared up once I got off caffeine. For other people their body is “allergic” to other things (e.g. apples).
I found a website once that people posted what they removed from their diet to remove the hemmorhoids or anal fissures; if you do a bit of searching you should be able to find it.
There are a variety of possibilites. One major one is Spleen Qi deficiency, so diet as someone suggested is a key and doing qi gong to supplement the Spleen and Stomach. Of course stess/liver can be attacking digestion, wood attacking spleen, need to know more.