From Kansas hey.. August last year I was at the North Texas Horse auction and there was this lady there from Kansas, the S&S or S&H ranch or something like that. Anyway she had about a dozen of some of the best trained and behaved horses I've seen in years. Said she trained them all herself. Mostly working ranch QH Geldings in the 3 to 7 yr range. That auction should be coming up again soon. If I see her I'll tell her about your horse if you want. Is your horse regestered?
As far as the sensitve skin thing, I've heard of horses with a condition called Shingles which makes the nerves in their skin more sensitive than normal and have symtoms similar to what you've described. In some cases the skin can be so sensitive that you can't even brush the horse. The good news is that there ARE treatments for it. I don't remember what they are but I'm sure your vet would know.
I've also known cinchy horses. Especially ones with low withers that don't help hold the saddle in place well and people are tempted to overtighten the cinch to try and hold the saddle in place which is very uncomfortable for the horse. The answer in this case is to use a breast collar to keep the saddle in place better and backoff on the cinch. The not wanting to run thing you mentioned sounds like an overtight cinch, maybe.
Has she actually been tossing experianced riders for the past 3-4 years? If so, she needs professional help
Good luck.