Was it towed with the front wheels off the ground or the rear wheels off the ground or was it a straight tow (all wheels still on the ground)?
If the rear wheels were off the ground or if it was a straight tow then if the transmission wasn't in Neutral the transmission may have been damaged.
Have you checked that the transmission fluid level is OK?
If it was towed with the front wheels off the ground or as a straight tow with the transmission in Neutral, then towing it in either of these ways would have been OK.
Have you had the car since new? If so check the length of the new car warranty period in the owner's handbook and if it is still valid, get it checked out under warranty.
Also try not to drive >5000rpm in 3rd gear until you get the transmission checked out.