It's such a problem that there are several agencies, like the Center for Orbital and Reentry Debris Studies which is tasked to tracking & making sure stuff up there doesn't run into spacecraft or the International Space Station or anything we send up there (like currently functioning satellites). Here's a little animation to give you an idea what it's like up there. They say they're tracking 22,000 objects up there.
It doesn't just stay up there - lots of times the orbits degrade & the space junk returns - & you get news headlines like "Satellite Heading For Earth" & "NASA Satellite Falls On Canada: No One Hurt".
If you didn't want to click the little movie up there, here's a similar image from the European Space Agency:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhp3sWHJzov_RFfP2pNB1BgSqj5rILRPBdGTqoFYFFNilWBekOXiribUrXPeRi9Epag-kOXJrmtvoMMXEzqRQztuEYiYEBwMPGJd0U7WJTuD5pwOBculkZs6M-AjO2pMprwqWNi/s400/space_junk_esa_big.jpg)