Losing important messages happens accidentally, well, if you have iTuens backup file you can still restore your iPhone messages, now I'll guide you how to restore iPhone messages from iTunes backup file
on computer with Coolmuster Data Recovery for iPhone iPad iPod.
Notice: Don't connect your iPhone to computer immediately, or the iTunes backup would be updated and you will lose your old iTunes backup file, and you can't get your messages back.
Step 1: Select Backup Device
Launch the iTunes backup extractor on Mac, then app would retrive all the devices that you have backuped on the computer before, and select your previous iPhone backup files from the list. Next, click "Start Scan", the problem will scan and display all the contents contained in the backup files.
Step 2: Recover Messages from iPhone backup
Just like the image below shows, you can click the icon to preview the messages. Then select and check those messages you want extract. At last, click "Recover" to start the extract. Then, there will be a dialog ask you to choose save address, you just need to choose where you want.
Great, that's all!