Hello, Borislav.
For the itching, can you try plain Vaseline? Try a cream for a baby's diaper rash can help soothe j pouch bum burn and itching. Vaseline, or Zincofax. After each BM clean the area with water, dry completely, then apply Vaseline. Try not to use dry toilet paper, try not to leave any poo behind, which can make more bad burn because your skin is raw. See if that works if Calmoseptine is not available to you.
For loose liquid stools, in my early j pouch days (last year), I found that baked potato, or a baked yam, helped make stools a bit thicker and slowed down. I avoided pizza because it was too much carbohydrates for my stomach and make me go even more, but for some members pizza works. The looser the stool, the more you will feel the acid burning because food is moving through your bowel so fast, nothing to absorb the acids. Some members say marshmallows help make stools thick. I never tried that (I'm diabetic). If certain foods are not making any difference to your BMs, switch to another food. Put chicken aside, try fish for awhile, or squash well cooked. Whatever you eat, peel the skins and don't eat any raw vegetables, nuts, seeds, or salads for now. Don't give up.