It can be sooo hard to determine whether the head butt you are observing is just being irritated or opinionated, or if its involuntary. Miniel is starting to head butt and I am sure its involuntary, but there's no other symptoms like you say. At this point I watch and wait. It may never turn into anything at all and Miniel's only about 19 months old, so I hope its a long time or no more symptoms. Maybe there's a PT in there causing this one symptom but no growing any further than that. I hope we both have the same luck Godmother. ((hugs))
I personally wouldn't treat at this time yet. I would wait until I saw a bit of confusion or the clubbing of the front feet when they turned, a laxness of their body, etc. I find then is when you will get the better results to treatment.