I am grabbing at straws for you with this possible solution, but it's worth a try.
Remove the connection between your iPhone and your computer; turn off your computer and turn off your iPhone. Wait a couple of minutes and then turn both units back on and reconnect your iPhone to your computer. Hopefully the two units will recognize each other and complete the connection.
When I have had problems with my iPhones or iPad, this is what I have done and it has worked. Sometimes this electronic stuff requires some magic and sometimes the simplest of solutions work. Try it. You won't loose anything but some time.
Good Luck,
bc