There are a couple different kinds of meditation, and although I'm not an expert on them, I know a little bit...
In some meditation, you focus all of your attention and concentration on one single thing eg. the object of your stress. That single-minded focus can help you better understand your problem, and possibly view it more realistically. I know that sometimes I'll worry about something which can then blow out of proportion. This kind of meditation can help you see the problem for what it really is, and make it look more manageable. So I guess this kind of meditation would be helpful if you had a problem that was stressing you out, and you wanted to solve the problem so that you didn't need to worry about it anymore.
There's also another type of meditation where the goal is to calm your mind and basically not think about anything. This is really helpful for if you always have a bunch of little, everyday worries going on in your mind, or if you have difficulties putting them out of your mind when you're trying to relax. It's true that it's very possible that those worries will come back after you finish meditation, but the meditation does give your mind some respite from those worries, so that you can better face them later.
Like I said, I may be wrong about some of these points, but I've done a bit of meditating, and this is what I've found that it does for me. I hope it was helpful to someone