Horse started stopping before a canter/gallop

Question
Hi, Do you think it is possible for a horse to suddenly start stopping on hacks out of boredom? Or is it more likely a health/pain issue? (This is a new behaviour after years and I'm confused)

Info= (sorry if long! Didn't want to leave anything out) My pony is 21 and has hacked out everywhere with me since I got her aged 9.(She is fast and lively)
About a year ago she suddenly started stopping in the same spot on a path I use alot and not wanting to go forward. At first I thought she needed the toilet (and sometimes she did) but then she would walk backwards and put her ears back when I asked her to go forward.
A while later she started doing this in a second place (both spots about a mile from the yard. I wasn't so bothered I thought as both places where before a big canter/gallop track I assumed she was being silly/excited about that.  But now she is starting to try the 'stopping' in other places. It is always in a place before I would take her for a gallop/canter and only in areas with a mile radius of the yard, once we get away she doesn't do it anywhere!
If I dropped the reins when she does this she just stands still or turns and tries to run home. I keep asking her go forward (walking backwards - and REALLY slow walking)and when she gets to the start of the gallop (past the 'stopping' bit), she will leap and bomb off 100mph and needs no encouragement at all!

I would hate to think she is stopping because of fear of something causing pain when she runs, but once she has started canter/galloping she has her ears forward and seems to be enjoying herself.
For the last few years I have been at the same yard/area,(lots of roads, hardly any grass tracks) and hacking alone as no one else rides. I am now bored of these paths and I can only assume my horse is, because if her box her and go somewhere interesting, or even ride further away from the local area to a new place she is back to normal and no stopping anywhere.

Her saddle has been re-fitted recently and I ride her bit less. She had a vet check and apart from usual old age stiffness they said she was in great health for her age. In the years I've known her whenever she has had an actual problem (like an injury or abscess) she makes it very obvious. This doesn't seem like that to me as the rest of the time she is running around everywhere!

Is she trying it on with me on the boring familiar paths, or something else? I'd hate to think I was forcing her to do something painful.

Answer
Hello Laura,
It's always good to check if there is pain involved, but if your horse wants to go to the barn and goes willingly, it's probably only behavioral. The goal is to find a way to make going further down the trail the easiest thing he is offered to do so he makes the choice to go that way to keep life simple. I don't know what your footing is like, but when he refuses to go you could agree with him- "you're right! I wanted to trot around the barn too!" Turn around and go work where he wanted to take a rest then offer him to go for a nice cool out walk on the trail. If he refuses to go repeat the exercise until he offers to walk beyond the stopping point. You could them let him stop and have some grass or just relax. We are trying to show him that when he comes up with his own ideas it's WORK it can even be happy work, but WORK, and when he agrees with you life is easy. Try this out and let me know what you run into, then, we will address different ways you can work on your canter.
Best Wishes,
Caitlin Day Huntress