pain after defecation

[mrkmmix]

I am a 38 years old male, non smoker.
One year ago, I started (all of a sudden) to have pain after defecation. Most of the time (90%) there is no pain during defecation, only after. Pain lasts for hours, resulting in problem sleeping, depression, etc.

Strange thing is if the stool is harder, the pain is much smaller, if the stool is softer is much worse. More stools during a day -> increasing pain on each one.

Had anoscopy (several), colonoscopy, MRI, stool tests, no fissure, no hem, no clue. They say that there is nothing wrong clinically.
Tried GTN, botox injection, all kinds of ointments, no help. Only warm baths offer some temporary relief. I always wash after defecation.

Any ideas what should I try next? Maybe a hospital that I should go ?

Thanks in advance.