@Sachin Vani You have to be in object mode to bake. So unwrap in edit mode, create your new image in uv image editor by splitting a window, name it and save it on your hd. Now, go into object mode, select the image texture node so that it is highlighted in orange, then hit bake. Then, re save the image under the image drop down. I had the same problem.
Then, I got a new problem that required me add an image texture to another object in the scene before bake the current one.