What's up with Tot?

I can't figure out if Tot has sensory issues, other issues or if he is just two.  Little Tot whines and cries so often.  He hates to be startled and will swing first and ask questions later if there is a loud sound.  Often he will cry like he is in extreme pain when he gets touched.  He does not always cry, sometimes he is fine, but the startled crying reaction happens a lot.  He is also my baby that yells at unexpected times and it can be quite startling.

He is also my most stubborn child at this point.  No encouragement, discipline, or redirection works consistently for him.  He may appear to listen, he may appear to comply, but very quickly he shows me he did not get the message.

Even in therapy when we are sitting and just talking about something mundane he pushes into me me, flips his body around, whines and twists, and moans.  

We work so hard to get him to use his words.  He CAN use his words.  With the others I can say, "Say I don't hit," and they will repeat it or whatever the issue is.  It worked well for me with Cy when he was younger and with Tyke to help them internalize ideas.  There are times when I say, "Tot, say, 'I will not throw toys.'"  He stands there and blinks.  No, I mean he actually blinks his eyes in big obvious blinks, not in normal eye movement, and he does not say a word.  I wait and ask again and nothing.  Then when I begin to move him to timeout or his room he yells, "I DON'T THROW TOYS,  I DON'T THROW TOYS."  So I know he heard me.

When I send him to do anything he doesn't prefer he just stands there.  He will not follow through with obedience.   One example is getting him ready for bed, at the end of the routine I tell both boys to go get in bed as I follow along.  They both head in the right direction, and Tyke obeys even though he protests and gets into bed.  Tot will just stand beside his bed.  He will not move until he is forced.

I can remind, coerce, and discipline till I am blue in the face on certain days.  It makes no impact.  Then when I finally show signs of anger, THEN he complies.  He usually pushes for the biggest reaction he can get before obeying.  

If all the kids are playing together Tot is always offended, or hurt, or scared.  This all means more crying.  I literally say a prayer before I go to him many times.  I really don't know what to do and I don't want to scare him by me getting angry. Sometimes he does seem like just a normal kid, but lately I am beginning to wonder if something more is going on.

Right now Tot is playing in his room, alone.  I feel bad for that, but we all needed a break.  After the initial protesting he plays happily enough.  I can hear him upstairs pretending to be a tiger right now.     Tot has been through a lot in his life and I also have to make allowances for his age.  I just cannot tell if I am dealing with an emotional and age issue or something more.

Has anyone ever dealt with this?  He startles easily and is extremely abrupt in his mannerisms, and incredibly defiant.  What am I missing?