His right arm moved slowly, but his left shrieked with searing pinpricks when he tried to move it, swinging it sideways and trying to lift it by his head, but his arm barely moved, only howling in anguish instead.
Maybe personal preference: consider two sentences here. (Having “but” twice in this sentence is throwing me off.)
…and trying to lift it by his head. But his arm barely moved,…”
2.
Had he just now heard some young woman’s screams and young men’s cackling laugh,…
I think “laugh” should be plural since you are referring to men. Or use “laughter” instead.
1.
His right arm moved slowly, but his left shrieked with searing pinpricks when he tried to move it, swinging it sideways and trying to lift it by his head, but his arm barely moved, only howling in anguish instead.
Maybe personal preference: consider two sentences here. (Having “but” twice in this sentence is throwing me off.)
…and trying to lift it by his head. But his arm barely moved,…”
2.
Had he just now heard some young woman’s screams and young men’s cackling laugh,…
I think “laugh” should be plural since you are referring to men. Or use “laughter” instead.