Horse major personality change

I have had my 8 year old QH gelding for 10 months now. When I first purchased him, he would go off on a trail by himself (he was previously used as a trail horse), stood still in the crossties, let me catch him, hardly spooked and was a very easy-going horse.
The past 4 months however, he refuses to leave the farm so much so that he whirls around and tries to bolt back to the barn and the more I ask him to go, the worse he gets to the point he rears and backs up rapidly while spinning. He has also been fidgeting in the crossties and almost every time I put him in them, he twists around in them until they snap and then he will bolt out of the barn.
When on a trail ride with others he continually bucked and would half-rear and fidget when I asked him to halt for any reason. He continues to buck and spook over the same things he sees every day.
He won't let me catch him and today I spent 15 minutes trying and every time I got close, he whirled away and kicked directly at my head each time.
He is perfectly healthy, no saddle problems, teeth done a few months ago, no hoof/leg problems etc. I don't let him get away with bad behavior either. If he misbehaves, I lunge him, make him back up, and move his hindquarters and shoulders away from me. I don't understand what is going on. I was riding him 2 to 3 times a week as well. He stays out 24/7 unless the weather was cold. He has been pastured with other geldings but right now is with three mares. I have a trainer but I'm to the point of selling him. He is getting more and more aggressive and I've had too many close calls recently.
Any advice is greatly appreciated thanks.