Atreyu, here are some factors we need to know in order to help you out:
-Model of your phone
-Did you opt-in to encrypt its contents/sdcard?
As far as I am aware, encrypting the contents of your phone is an opt-in procedure on almost every device. So, if you didn't do that previously, you will need the following:
-Micro SD adapter
-Very small screw driver
-(optional) phone disassembly tool-kit
From there, take apart your phone, locate the internal sdcard, put it into the adapter, and plug it into your computer with either supported hardware or a card reader. After that you should be able to browse the contents of your phone. This is where proxx was saying it will take some skill to find what you're looking for...if the messages were previously deleted, the easiest thing you can do would find specialized software for your model of phone to view caches with hidden/deleted files. If you know how to use linux, you can do the same thing without software and use some "ls -la" wizardry. Good luck!
Sidenote: -_- I feel like I just repeated what proxx said, but with more words...