You switched to another phone? If you did not have the $10 smartphone data fee before, you will now. Once you activate your Optimus again, you will receive the monthly fee, even if you did not have it before. I am being very careful to keep my Optimus activated for as long as possible, so I don't get the fee.
Yeah, that would be weird if my phone sent random text messages. I suppose you made the decision that was right for you. I happen to have a "rooted" phone, which allows me to block data for specific programs, like messaging, if something like that were to happen to my phone. I'm glad that the Optimus has an "Open Device" policy that lets me have root access without voiding the warranty or Sprint terms.
Anyway, it looks like Will thinks it's a problem with Android, and not with the phone. However, I have not experienced the problem, and you and I use the same operating system. We have 3 Optimus phones on my plan, averaging 1300 text messages per month, and all of them go to the intended recipients. One thing I know is consistent between the three phones is that we only send messages to Google contacts. Do you type in the phone number or select a Google contact when messaging?
Check out a fun infographic that teaches you how to increase storage, enhance security, improve battery life and clean your device.