How hard is it to get hired at Macy's or other retail stores after Christmas?

So I really need to get second a job after Christmas to make some money to pay off (what else) annoying bills. I would like to work at Macy's or some clothing retail store (like Express or Pac Sun)...I'm a guy btw...how hard is it to get hired at these kinds of stores? Are most hiring or is it unlikely? Also, do you usually apply online or at the store?

Most major stores will only do major hiring pushes before Thanksgiving, summer, and back to school time. It'll be harder to get a job outside of these times but not impossible. A lot of stores do a "seasonal to hire" type deal where many of their seasonal employees are offered "first dibs" at a full position if they do well during the peak season.
However, many places (like Express, PacSun) have a lot of employees who are students and either go back to school after the winter holiday or get bored and quit. I highly recommend waiting until like the 3rd week of Jan and going in person to the stores you are interested in to see if they have any vacancies; especially if you have availability opposite that of a high school students (morning, late nights). Applying in-person wearing clothing appropriate to the store also gives you an edge if the manager on duty has a chance to see you. As a former ASM in a store geared toward 15-25 year olds, I took note if someone who "looked the part" came in a asked for an app.

It's ridiculously easy. If there's any major (or even remotely major) mall near you, it's always possible to get a job in retail. There is always a teenager or senior somewhere whose job is not of much importance and eventually just drops it. This happens quite often and the bigger the mall, the more openings. If you're really going to wait on one particular retail store, you may have to wait longer. It's all about preference from there.

Some stores will be laying off since they usually need the help before Christmas, but if you stay with it and keep trying, you'll find a store, while some are laying off, others will need help because the college kids will be returning back to school.