Im pretty sure wheel bearings are pressed into the hub or whatever its called your best bet is to just replace it there really is no way to tighten it. However im not totally sure i havent replaced a wheel bearing on a f150 before.
First of all I have no clue why the guy doing a inspection looked at your wheel bearings. He would have to taken off the wheels, then rotor/caliper and then pulled it out. Its not too hard but takes some time and I've never heard of them being tightened. But you can replace them. Like I said its not too hard if your handy but can be frustrating and will take some time(no more than 30mins a bearing). I could try to explain it but you probably wouldn't understand what I'm talking about (I'm not good with words). Try looking up "f150 replacing brake rotors" or some thing to that effect on youtube. I know theres some videos out there.
You can tighten wheel bearings depending on the vehicle. I've never done them on a Ford but I have on a Kia, etc. There is a tension nut that you can remove, pull bearings out, clean, regrease, reinstall and tighten.
You inspect them the same way when you check for loose tie rod ends and what not. It's normal and should be expected that a mechanic would check for freeplay when inspecting your vehicle.
On a 4x4 you have pressed in hubs. They bolt in and don't need to be pressed.
You have a 4x2 which means you have tapered roller bearings. After pulling the bearing cap off there's a cotter pin you'll remove (and replace), a slotted cap that fits over the nut, just pull that off. Then there's the nut. You'll want to tighten this all the way, turn the wheel clockwise and counter clockwise a few turns. Then loosen the nut 1/4 turn. It's that simple. Put the cover back on the nut and the new cotter pin. Don't forget the cap. You should clean the old grease and repack it with new. This involves taking off the caliper and you should replace the grease seal as well.
I just replaced mine on my 02. You take the wheel off, take the caliper off, dust cap, cotter pin, nut ring, nut. The rotor will come off and there are 2 bearings on each side. Clean all the old grease out, re-pack the bearings or replace and pack the new bearings. New dust seal would be smart since they are cheap. You tighten it up a little and spin the wheel to get the bearings to seat and then loosen up the nut. It won't be too tight, a little more than hand tight or so. Put all the stuff back, new pin, and you're done. Don't be shy with the grease pm if you need help, I have a Haynes also if u want to see their step by step but it's pretty much what I said.