Your dragon is way to hot in that 10 gal tank. No wonder he doesn't want to come out of hiding.
Get him out of teh 10 gal tank and put him into something liek a 20-30 gal long tank. A rubbermade container would serve in a pinch, as long as it is big enough. However, be careful with the heat lamp, as if the bulb touches the plastic, it can melt it.
Having him outside certainly is good exposure to UVB light..but how are you putting him outside? Is he loose, in direct sunlight, still in that 10 gal tank? Direct sunlight can kill a bearded dragon if its hot enough. Even if the air temp is 75F, it can quickly get much hotter than that under direct sunlight with no or little breeze, especially if he is in a glass tank (think car in the parking lot)
I suggest soaking your dragon for 20 minutes in luke warm water (around 75-80F). THis will ensure he has plenty of time to hydrate himself. Just make sure the water isnt' too deep and there is a rock or rolled up clean facecloth for him to sit on, to rest.
What size insects are you trying to feed him? If crickets or whatever are too big, he may feel intimidated by them and they could pose an impaction or choking hazard if large enough.
Try soft bodied and active insects, such as phoenix worms, small wax worms (dont' give too may wax worms, as dragons can get addicted to them), small to medium silkworms and horn worms (if you can get them small. Adult size of these last two worms would be too big for him right now).
I also suggest reducing the time he is outside and how often. An hour a day for about 5 days a week, is enough for him to get all the UVB light exposure he will need. This is mostly to help reduce the stress of being outside for several hours. Outside to a baby bearded dragon can mean sitting duck for the first predator that comes along (which is basically anything big enough to eat him..birds such as crows, seagulls, birds of prey, etc. Also cats, dogs, and wild predators.
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PHLdyPayne