Q: retrieving old messages from Iphone?

Unless yo have a back up that contained that message (i.e. was still on the phone when the back up occurred), no.

To avoid this issue, there are two things you can do:

1. Settings app > Messages > Keep Messages [set to the time frame you wish]
2. Don't relay on text messages to store business critical information.

Even if it was still on the phone, scrubbing up in a thread through 2 years worth of conversation will likely crash the app once you get past about 1 years worth or so, depending on how frequently you chat with this person. There are some 3rd party message extractors out there for your desktop, although I don't know if they still work with all the recent security updates that have been made to these devices.

Sorry man.

This will result in a loss of any data that has been added to phone since that back up was done.

https://support.apple.com/en-us/HT204686