Here's the thing; if you're not pushing yourself beyond the boundaries of your abilities and beyond what you can do comfortably, you're not growing. If you stay there long enough you will begin to resent it.
The feeling of being stuck comes because you have reached a local maxima. I remember those words when I was learning Machine Learning in University. We had to learn about hill climbing algorithms, and stuff. It sounds interesting now but it was not back then.
When you reach a plateau in your life, it comes with the feeling of being stuck. Being stuck comes with feelings of resentment, confusion, anger and irritation with everything around you. You can't explain it, you desire more but can't reach it.
How do you get unstuck?
Widen your sphere.
Do something you have never done before.
Meet new people.
Try new things.
Keep an open mind.
Join new communities and engage with all your heart.
When you open your heart to new experiences, you will find that without changing anything else, your outlook in life improves.
Try it.
Do it, even if you have to do it scared.