Suggestion

I agree with Mahesh that "Understanding the process of bug fixes and changes is very common and complicated". Most developers want to write new programs. Maintenance programming is more common. From the point of view of management, you must earn the opportunity to do new development.
 
I think an important question is if the changes that you think are unnecessary are changes that upper management considers important. If so then you are likely to get that feeling wherever you go; most companies will likely have changes that you disagree with. If however the changes are requested by people that have personal reasons to request the changes then perhaps it is better to go elsewhere where the company is more productive and healthy.
 
It is common for programmers to disagree with management. Expect it to happen. If you do hang in there then one or two things might happen. You might get experience that will help you get another job. Experience can help. Also if you hang in there, then you might get the opportunity get better work within the company later. If someone is managing things in a way that is unproductive then perhaps if you hang in there you will still be there after they leave.
 
It depends a lot on how unreasonable the unreasonable changes are.

If you can find a better company, you should leave it. First thing in a job is, you must like the company and the work you do. Otherwise it becomes a burden. In the meantime while searching for a new job, also focus on the changes current company is giving. Understanding the process of bug fixes and changes is very common and complicated. At some point, every company will ask you to do that. 80% of projects are fixes and changes. Only 20% projects are new and exciting.

Good luck!

Leave it man