Again and again the same questions.

In English we have the words: suffer and torture.

e.g. I suffer from guilts

e.g. He is torturing his children

The easy words are:
(a) страдать = suffer
(b) пытать = torture

The difficult words are:
мучать(-ся) / замучать(-ся)

и

мучить(-ся) / ???

Question 1st:
Как мучать(-ся) / замучать(-ся) спрягается because wiktionary gives two options

https://ru.wiktionary.org/wiki/%D0%B...B0%D1%82%D1%8C

https://ru.wiktionary.org/wiki/%D0%B...B8%D1%82%D1%8C

Quetion 2nd:
When I use the word мучить(-ся)