It is hard to see our children not being like the others and you are right to be concerned. It can be an easy as removing something from his diet that is causing inflammation to an area of the brain or it may be that he will need a medication for some time. I would get him to a DAN doctor, http://autism.com/dan/danusdis.htm and you can find lots of information about sensory issues and recommendations of where to go from http://www.tacanow.org/resources/autism-web-links.html#an...
Disregard that these are autism websites. The information contained there is good for many different diagnosises. You'll want to check out the information on diet on the www.tacanow.org site as well.
For now, I would delay anymore vaccines until I knew what was going on with my son.