Thank you. I followed the above link and tried typing in the *#06# as indicated. This resulted in a message indicating that this was an invalid action. I then found my IMEI number through settings and typed it in. The website reply was that my phone could work with Verizon. This was quite obvious since I had been with Verizon all along. It didn't really answer the question of whether it was locked to them or not.
I next participated in the online chat with a Verizon Rep. She stated that my phone was never locked to them and that I could switch carriers as long as my phone was paid off. I then asked if the practice of locking them was true in the past. She said maybe. I then specifically asked if I could switch to Straight Talk or some other carrier. She repeated yes as long as it is paid off.
So it sounds like the "lock business" is not an issue. I think part of my personal problem is that I would like to have cellular on my iPad as well as the iPhone and I don't know if they have such an arrangement.