Yeah, its pretty easy to get pigeon holed. Especially when you are good at something. Because it becomes an easy way to make money. Since you already have the necessary skills.
It's why its important to pick personal projects and really push yourself in new directions. And be your own art director. Make revisions, act a shitty client Sometimes you need feedback from others. This used to be a great forum for that. Maybe with the reviving of it, it can be again.
Also a good idea to branch out and learn about something unrelated. I love watching crash course videos on youtube. anatomy, biology, chemistry, history. They have plenty of useful stuff to get your brain churning.
In the last couple of years i seem to have drifted towards a more technical role, rigging, etc and now i want to go back a bit towards design and aesthetic development. So im trying to get personal projects finished with a strong focus on design. Shapes, form, composition etc.