Is it possible to shrink a leather jacket? Do they have the tendency to shrink or stretch?

After over a year of searching for a leather biker or bomber jacket at thrift stores/online/leather stores...I finally found one I liked that wasn't crazy expensive. It's a size small, which is what I usually wear, but it seems a little big. That might be because it's kind of stiff...is there anyway to loosen it up? I've been wearing it around the house while I do chores, watch tv, etc., in hope of making it look a little more worn. Also, so I know for future purchases, does leather tend to shrink or stretch over time?