Am I imagining things?

[FrankieDurleigh]

So once again Piglet is showing signs of lameness.
He had an abscess which was taken care of and was fine. 2 weeks after he had a corn, trotted him up on Tarmac and in field and is fine. He is bombing it in the field, bucking rearing so I know he's happy within himself. I've taken him out since and he is fine most of the time but with the occasional head bob during trot (not all the time) he has for the first time since owning him started to spin in the road, this was sorted with a stern word and persuasion, now he's doing this occasional head bob.

I immediately stop and turn him to go home and as soon as I do this he is pumped up moving beautifully.
I had the farrier to check his feet and he says there is nothing wrong.
I've had a vet look at him and she says its him playing games??

I'm so paranoid that he's lame that am I seeing things?
If I persist and push him on it goes and we have a lovely ride out, but I'm worried is it the adrenaline that is making the pain go away?
My sister has advised using bute for a couple days and see if he continues to do it, this maybe proving that he knows if he bobs he goes home?
But is that risky?
Any help appreciated.

 

[Shysmum]

I've done a bute trial with my pony before - I had to get the vet to give me the bute, so explained what I was doing and he was fine with it.

In the end, it came down to thrush with Shy - might be worth checking for it again ?