What Causes Shaking And Numbness In Hand?

hi, i have 25 year old, and since 3 or 4 year ago my hands started to shake a bit and my right hand gets numb, specially when i' do some physical jobs that involve my hands (i'm a civil engineering). I went to a neurologist and all the test were fine (TAc of the head, MRI of my spine, TAC with contrast of my abdomen), what could cause the shaking?