My brain feels loose

For the past week if I walk up stairs, sprint, do crunches, jumping jacks, etc, it feels like my brain is bouncing inside my head. If I’m not moving or just walking I feel perfectly fine. It slowly builds up from a dull pain to a sharp pain, but if I stay still the pain goes away. I was thinking maybe it has something to do with my neck and i need to go to the Chiropractor. Any suggestions on what this is and how to deal with it?