Reflexives are used where the subject and object of the verb are the same:
I comfort myself
You can comfort yourself
Here they are not. Music and painting are the subject of the verb, doing the comforting. So the object pronoun must be you. However, it is possible to introduce you as the subject, in which case a reflexive pronoun would be appropriate.
Music and painting can comfort you and reduce your stress.
You can use music and painting to comfort yourself and reduce your stress.
(Note the omission of the superfluous it can in the first example; you don't need to repeat that.)
Sidenote: Reflexives can also be used for emphasis, but in that case they are always paired with the subject pronoun and are not used as object pronouns, as in "I myself use music."