I've recently started using blender, and was working with it just fine, when I accidentally changed how the scaling and rotating works. Now when I try to scale something, it scales as if the selector was the senter. Axis locked translations are also affected by this, as I have to find the selector to translate it.
If your selector is what it is scaling to, then you may have changed the Median point, or bumped your keyboard and it changed.
The third little box on the end of your screen will have the options to change the median point.
The original option you were probably using was the one called median point before it changed. just click on that one and it should fix it.