Hmmm...I would think about consulting a new doctor about the foot problems first. If your son is having chronic pain problems, that could certainly affect his disposition.
As to the general unreasonableness and tantruming--yep, I have conversations like this with my son regularly. He's upset and it is somehow my fault for not intuiting what is wrong. Speech therapy has helped somewhat with him being able to articulate the problem, but when he's on a tear, sometimes he just has to work his way through it. (Preferably in his room, where I don't have to listen to the ranting.)
