It's probably good to start with the simple, easy rings first. Have you tried clearing the cache and rebooting? Here is a link to the instructions: (I know the link is for a Moto X...the Razr M and Moto X instructions are the same with Kit Kat)
Like bigmatt503 said, your data isn't in use. It's just the 4G icon that's staying lit up. The up and down arrows indicating data transfer aren't active when you're on WiFi.
The reason for this is VoLTE. After the last 4.4.4 update, the Verizon S5 is VoLTE capable. Since VoLTE uses LTE for calls, it needs to maintain a connection with the LTE network. It will do this regardless of whether you've enable VoLTE or not.