When you disconnected the phone from the PC did you properly "eject" the device from the USB connection?
Try settings > SD card & storage and see if the SD card is listed as unmounted?
If that doesn't work, turn off the phone, remove the battery and SD card from the phone. Use a separate card reader to verify the computer can read the data on the card. Copy the data to the computer in a folder for a backup. Now see if the phone will read the card after reinstalling it. If not reformat the SD card in the phone. You might have to reformat it from the computer if you can't format it from the phone. Once the card has been reformatted, you can copy back the data to the SD card using the card reader to be safe if mounting the phone to a computer as a disk drive causes problems.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.