Suggest Remedy For Pain In Rectum

I have been experiencing pain in my rectum for a while, recently it got worse, as when I sit during the day on my work desk it gets unbearable. I have tried washing it after taking shitting, but it pain then as well, It feel like I touch a cut in my rectum. But when I try and see it with the help of a mirror, everything look sweet. What is it? But for sure, I am finding it harder to sit for more than 10mins at a stretch.