By "not active at all" are you referring to airlock activity? That's
never an accurate indication of fermentation. It is a vent to release excess co2..not a fermentation gauge...more than likely the mere act of moving your fermenter voided out any excess co2, NOT that there is anything wrong with your actual fermentation.
Your beer will ferment whether or not the airlock bubbles. If it's not bubbling it usually just means that doesn't need to release any EXCESS co2. Fermentation is not always "dynamic," just because you don't SEE anything happening, doesn't mean that anything's wrong, and also doesn't mean that the yeast are still not working dilligantly away, doing what they've been doing for over 4,000 years..
Now to your question of adding more oxygen...It is NOT needed, nor is it a good idea....once fermentation begins oxygen is BAD for beer.....In high gravity beers there is some discussion of adding more oxygen within the first 12 hours..but that is for HUUUGE beers like barley wine...
But not a pale ale. You will do more harm than good.
Besides there is some talk on yeast websites that Dry needs very little oxygen to begin with since O2 is needed for reproduction, and there are already plenty of yeast cells to begin with.
Just relax, there is nothing wrong with your beer. Fermentations just don't STOP after they have started...They slow down when they need to, but really everythig is fine...
Just relax, and walk away for at least a week..everything is fine. Your beer is fine, you just have noobitus, the tendency to worry incessantly about your beer, when in reality it is much stronger than most new brewers give it credit.