Why is it that when I plug my iPhone into my computer and press "trust", it disconnects my phone and reconnects it, and still does not connect to iTunes??

When I plug in my iPhone, it connects and begins to charge, then asks me to "trust" the computer. When I select "trust", rather than connecting to iTunes, my phone gets disconnected and then it reconnects again and continues to charge but does not connect to iTunes... I have tried restarting both my computer and my phone, I have tried uninstalling and reinstalling iTunes and I've also tried connecting my phone with different USB cables and connecting them into different USB ports... Still nothing is working.