Welcome to the forum.
There is a lot of good information in the 4th grn section, highly recommend you take a look through there.
Your noise could be a number of things. Could be normal or a problem. Some additional information would be helpful.
What is the full set up on your truck? 2wd or 4, crew cab or other, bed length, any modifications like a lift, bigger tires, etc? What gearing do you have, all the details. Are you original owner and have you noticed problem before? Do you get sounds leaving truck t/h mode off? Does it change if you turn off air/heat system while towing?
How heavy exactly is your trailer, and how much weight do you have in truck when towing, exactly. You could be over your capacity to tow and the sounds are your truck working hard. Don't go by guess, get your weights and then your exact configuration will help others be more aware as the offer ideas.
As much information as you can provide will make responses that much more helpful. Good luck.