Could a sore lumbar region be causing these problems?

My horse whom I've had for coming up on 2 years has a sore lumbar region. He's a 14y/o paint gelding. Who for the length we've owned him has been a bareback pleasure/trail horse. I noticed him heavy on his forehand and that he has some trouble bending(more to one direction than the other), he also doesn't canter on a line. And another side note he rubs the dock of his tail up high until he develops a bald spot(despite regular worming/flysprays/mtg/sheath cleaning)
I'm calling the chiropractor out in 3 weeks to have him evaluated but I know he is sore in the lumbar region on both sides, more on the left.
I just graduated college and have had the time to ride everyday trying to get him ready for shows. Took some time off after noticing sore back but it didn't get better.
I've been looking at this article and thought wow this seems to answer a lot of questions.
He isn't girthy but I HAVE noticed he will back up once or twice when I try to mount, but then stops and stands after I walk him forward. And also(this blew my mind), Friday night after w/t/c and some small cross rails we stopped and stood talking for a moment and he started bobbing his head and actually pawed at the ground! He NEVER does that, it's rare that he pins his ears! He's the bombproof dead broke kid/husband/grandma horse that we can do anything to. I wonder if maybe he was extra sore and standing still was bothering his back? He'd never done that before.
So now I'm afraid to really ride him because I don't want to cause him pain.
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Book Chiropractor specialising in the treatment of horses from Back to Straight
There's the article, sorry
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