Sound in head!!!!! pLEASE hELP

Hello, my name is Travis. I have been experiencing some scary things lately. I notice that when i jog in place or if i jump up and down in one spot i hear and feel something coming from my head. It sounds like a quick thump almost like liquid moving around in my head. If i jog in place for a minute straight ill hear the sound somewhere around three or four times. Sometimes not all the time but sometimes i also get a quick pain when i hear the sound. I dont know if its possible to actually hear fluid moving around in your head but i have been to an ENT and he said my ears look fine. I also hear this sound if im jumping on a trampoline or jumping up and down in one spot. I had an MRI of my brain which showed a Mega cisterna magna which is a larger than normal cisterna magna, one of the fluid filled spaces in the brain. Idk if maybe this is whats causing the sound and pain or if it has nothing to do with wat im hearing or feeling. Also i must add that im currently seeing different neurologist to find out wats causing a sharp quick pain in my head that occurs multiple times a minute. The pain last just a split second and then goes away. It feels like a quick electric shock of some kind inside my head and is also triggered when i tap my jaw with my hands. If i merely tap the sides of my jaw i feel that pain coming from my head. If someone could just give me there opinion on at least the sound im hearing from my head that would be greatly appreciated. Thank you sincerely Travis