Text already showing when I compose a new SMS on iPhone 4s

Good evening all!

First time poster with a weird problem. At some point a few weeks ago I forwarded a SMS to somebody. Ever since then, whenever I go to compose a new SMS, that previously forwarded SMS appears in the text box. Even weirder, if I try to forward another text now, I get the same darn text showing in the text box, with no sign of the message I was trying to forward.

I'm on 6.1.3. When I restored the phone as a new phone, it went away, implying it is something IOS or iTunes is forcing to happen, but I need to keep my old backup as it contains all my old SMS messages.

Anybody any ideas or a solution? It's really annoying so I'd be really chuffed if someone could help.

Thank you 🙂