Set Elbow

I have this numbness feeling in my arm, especially in my elbow area?

Like, I won't do anything and it will go numb then I do something like shake it and it goes away. Especially bad when I lean on something or set it up highish.

What could cause this?

My grandfather also has a lot of problem with his arm too. So could we have something similar.
I'm 16 btw.

neck problems can cause limbs to go numb.

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