You can express yourself musically by banging a guitar against a rock if you prefer, if that’s the best way to use it to express yourself. It’s so narrow to talk about creatively expressing yourself “musically” or through “dance” or “art” or “poetry” or whatever. As soon as you do that, you start to judge the end product according to how good an example it is of “a song”, “a painting”, “a poem” or whatever instead of how good it is at creatively expressing the artist.
If you want to express yourself photographically, you can take a selfie on your phone, print it at Boots and edit it with Magic Markers if the end result expresses how you feel. Someone else might see it and get it because they feel the same way. Or maybe they won’t. It doesn't really matter. Whether or not it’s Art is debatable but it’s undeniably creative self-expression. Banging a guitar against rock or taking selfies on a phone is creativity happening and anyone can do it. Pushing “Art” out of the equation and just expressing yourself however you feel like doing it democratises creativity. It’s not restricted to an elite group of people called Artists. Anyone can do it.