I had the same problem and I have resolved it by going through the following steps.

If you need to keep your changes -

1. First you need to run git checkout master command to put you back to the master branch.
2. If you need to keep your changes just run git checkout -b changes and git checkout -B master changes

If you don't need your changes

1. To removes all untracked files from your branch run git clean -df .

2. Then you need to clear all unstaged changes within your repository. In order to do that you have to run git checkout --

3. Finally you have to put your branch back to the master branch by using git checkout master command.

I had the same problem and I have resolved it by going through the following steps.

If you need to keep your changes

1. First you need to run git checkout master command to put you back to the master branch.
2. If you need to keep your changes just run git checkout -b changes and git checkout -B master changes

If you don't need your changes

1. To removes all untracked files from your branch run git clean -df .

2. Then you need to clear all unstaged changes within your repository. In order to do that you have to run git checkout --

3. Finally you have to put your branch back to the master branch by using git checkout master command.