It seems like you are having an over-active inflammatory response to the minor bumps. The brain's ability to regulate inflammation can become compromised after an injury and so it will over-react and pump out too much inflammation in response to a given stressor.

So your brain needs to learn to stop over-reacting. BurritoWarrior had success with the Targeted Exposure method. Check out his thread: Repeat "Concussions" From Low-Force Events? My PCS/Atypical Migraine Story

I also describe a gradual re-introduction of activity in my Concussion Protocol.