You can try shutting down the computer and disconnecting all USB devices including hub. Start up with no USB devices connected (except for standard keyboard and mouse if used). Do this to reset the shuffle
http://support.apple.com/kb/HT1655
Run iTunes. Connect shuffle to a direct USB on computer.
If that does not help, there are four possible causes. Rule them out one at a time, if possible.
Bad USB port on computer - You mentioned an iPod touch. If you are able to connect to iTunes with the iPod touch, using the same USB port, I think you can rule out a bad USB port.
Bad USB cable - You would need to try your USB cable with another 4th (or 3rd) gen shuffle, OR try your shuffle with a known-good USB cable from another 4th (or 3rd) gen shuffle.
Software problem on computer - If that iPod touch works properly, the computer's software is probably OK. If iTunes is not the latest version (my current Mac version says 11.02), you could try updating it. But I think software problem is ruled out, if the iPod touch works fine, unless your iTunes version is really old.
If you can rule out those three possibilities, then the remaining cause is a hardware problem on the iPod. If you have an Apple Store nearby, you can take it to the store's Genius Bar. If you weren't able to rule out a bad USB cable, I'm sure they have a cable there to use as a test (but take your cable along). If the shuffle is less than one year from purchase date, it is under warranty. You can make a reservation at the store's web page.
http://www.apple.com/retail/