Why do I have these weird things?

My hand just shakes for no reason. When I'm holding something and my hand is shaking what I'm holding falls out of my hand. I also get this tingling feeling that a spider is crawling up on me even though there's no spider. I also get some weird back pain. Light back pain that is usually a few minutes... show more My hand just shakes for no reason. When I'm holding something and my hand is shaking what I'm holding falls out of my hand. I also get this tingling feeling that a spider is crawling up on me even though there's no spider. I also get some weird back pain. Light back pain that is usually a few minutes long. My leg also jerks. Why do these things happen to me?
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