If a Pokemon has Rock head it will still take recoil damage.
>A Pokémon will still take recoil damage even if it has an Ability that would prevent it, such as Rock Head.
It can strike a critical hit, and the recoil would double.
Since you take 1/2 of the damage dealt, you would take more damage if it results in a critical hit.
>Struggle is capable of striking a critical hit.
Hope I helped.