Adding to the other comments: object pronouns can be attached to the end of an infinitive, a present participle (the -ndo form), or a positive imperative. They cannot follow or be attached to the end of any other verb form. If the verb consists of more than one word, and one of the words is an infinitive, a present participle, or a positive imperative, you may be able to attach the object pronouns to the end of that word. If none of the words in the verb is an infinitive, a present participle, or a positive imperative, then the object pronouns MUST go immediately before the first word of the verb.

The verb is the same: quejarse Tú te quejas is present simple Tú te quejaste is past simple. Espero haberte ayudado

It's not the same. "Quejaste" is past simple. You are missing the pronoun there: "Tú te quejaste" "Te quejas" is present simple i.e. "tú te quejas"

El verbo "Quejarse" es un verbo pronominal , es decir, necesita de un pronombre personal átono (me, te, se, nos, os) para ser conjugado correctamente. "Te quejas" estaría en presente. "Quejaste" estaría en pretérito perfecto simple, es decir, en pasado. No obstante, "tú quejaste" está mal dicho. "Tú te quejaste" sería lo correcto.

Es lo mismo pero en diferentes tiempos... según el contexto en que lo quieras usar. saludos desde Venezuela.