The terminarion or sufix "-ok" it's for "I" and "sz" for "You" right?
Yes.
Állok. - I stand. Állsz. - You (singular) stand.
Would this also translate to "You are standing."?
Yep. Those are the same thing, as far as Hungarian grammar is concerned.
Is there any difference in the meaning of "you are standing" and "you stand"?
Very confusing word