My Pet Turtle!

Question
I recently got a turtle from a friend. Now I don't know what kind of turtle it is or the gender. But I safety assumed it was a male and named him a Donatello! Anywho, Donatello has been doing so well the past couple of months! He's grown so much. But recently (past two days) he's been scratching at his pebbles at the bottom of his tank, scratching his belly on them too and wiggling his tail (butt). What is he doing exactly? Should I be concerned with his health?

Answer
Hi Ciara,

I need more information:  size of tank, type of basking and UVB lights you're using, type of filter, water and basking temperatures, and complete diet.  I'd also like to see a clear picture of the turtle.  You can't care for a turtle properly if you don't know what it is.  

How much has he actually grown?  This can actually be a problem.  Turtles aren't meant to grow fast and if they do it can lead to shell deformities and other problems (another reason I'd like to see a picture).  Once I have more information I can give you better advice.  Thanks!