The phone is Samsung SCH-U550 Im trying to enter letters for a pin, (this is not for texting) and the shift key appears not to be acting like Im used to on other phones. Its probably user error.

For the first letter entered, I need to use the 5 key and no combination of the shift or of the 5 key will get it to do anything but enter a string of 5's. Ive tried holding it, and as usually works, multiple presses of the number to get letters. The (alpha) pin I need to enter is for verizon backup assistant so its in a text box within that program.

Here is a link to the Manual

Thanks for any tips...

Have you checked to see if there is a soft option button (left side) to toggle between numbers and letters?

Wait a sec... you said this is a PIN? Not texting? What function are you using when doing this? Are you browsing the web? If you are in dial mode you can only send numbers. You PIN, if dialing, is always going to be numbers.