You might consider using a different font color because that is really difficult to read against a dark grey background.
Wall of Pain = BAir spam, not UAir. The goal is to control the space between them and the stage and prevent them from returning with strategically positioned back-air kicks to knock them back away from the stage.
You don't always have to jump between BAirs, it's all about positioning and controlling the space. Just practice chasing them off the stage while facing backward and try to hit them with as many BAirs as you can. It will be tricky at first, but you'll get the hang of it.
I mean, I guess you could wall of pain upward as well (with UAirs), but the primary goal in that case would be to knock them out the top of the screen for a kill. You don't have to knock them out the side of the screen to kill them. And keep in mind that UAir is not nearly as safe as the BAir... many characters will be able to directly counter it with downward attacks, and most characters can avoid it by simply moving sideways or dodging.