I Need Help Finding Out Whats Wrong With My Brain

(18M, 6'1", ≈280 lbs, white)

Hello! I have a quick question about what the heck is wrong with me.

(This is going to be a very weird explanation of my experiences, I sincerely apologize for my crude explanation.)

Basically, for as long as I can remember, I have had this tic-like thing that happens to me whenever I am nervous, and especially, excited. It is a feeling that boils up inside and quickly "releases" with me kind of jolting my arms and fingers, as long as my head twitching a bit and my face scrunching up. Only when I REALLY excited does it get very noticeable, but usually its a quick thing that goes unnoticed.

Oddly (and unlike most people I've met with actual tics) I can control it. I can force myself to not do it, but usually it's not worth it. I can also force myself to do it, too. (this is the part that is hard to explain) Basically, it's like forcing goosebumps. I force the feeling and I can hold it for a second, I start shaking a bit, and I have to stop.

I am so sorry if I sound insane, I've asked friends, my mom, and google a few times, but nothing solid came from it. I'm not, like, desperate for answers, the "tics" don't bother me, but I was just curious about them.