Learn Spanish (Latin America): Pintar es mi pasatiempo favorito para relajarme.

In English, we often use the "-ing" form (the gerund) as the subject of a sentence, like "Painting is my hobby." In Spanish, when a verb acts as a noun or the subject of a sentence, you must use the infinitive form (pintar). Using pintando as a subject is grammatically incorrect in Spanish.

Why do we use the reflexive relajarme here instead of just relajar?

The verb relajar by itself means to relax something else, like a muscle, or to calm someone else down. When you are the one resting or calming down, you are relaxing yourself. This requires the reflexive form relajarse, which becomes relajarme because the sentence is from the "yo" (I) perspective.

Why is the pronoun me attached to the end of the verb in relajarme?

Because relajar is an infinitive (an unconjugated verb ending in -ar, -er, or -ir). In Spanish, object and reflexive pronouns like me must be attached directly to the end of infinitives, gerunds, and affirmative commands.

Could I put the me before the verb and say para me relajar?