zoro's pain tolerance is the highest in the series, even higher than the WSC, kaido cried from his own boro breath lol.
-getting shot by nails---silence
-taking a scythe through the shoulder---silence
-getting hit by indra---silence
-taking hakkai---silence
-taking thunder bagua---silence
it may take indera/hakkai/thunder bagua pain x2 at the same time to make him scream.
zoro's badassitude is only rivaled by shanks's