I feel right now I am doing things that “I am good at” but they are not what “I want”. Does that mean I want something which is not my gift? Can I desire to do something which is not my gift?

You probably have more than one gift. While you are good at what you’re doing, it’s not the desire of your heart. Whatever you desire to do most likely is something God has put in you, equipped you for, and gifted you to do. 
 
I can do a lot of things well, but that doesn’t mean those are my calling or purposes from God. The more I function in my areas of gifting, the better I perform. And when I couple my giftings with my calling, I soar. That’s how it’s supposed to feel–like soaring. Not just that you’re doing a good job, but that you love, thrive on, and are fulfilled by what you’re doing. 
 
For example, I’m gifted at speaking. I speak in my job and it’s good, fun, and better than other things I have to do. But when I speak in a ministry context, I am re-energized, charged, and the best version of me that I can be. So there’s things I’m gifted in, and things I’m called to, and when the two come together — wow! And if I could get paid for them–that would be the unbeatable perfect scenario!