What Causes Constant Shivering Of Hands?

I am 26 yrs old woman.I have asthma.My hands started shivering before one year.nowadays it has increased.i am not married yet.I had viral fever last week and it lasted 10 days.My blood count was low and I was given injections for that.and the blood count became normal.and my ECG,X-ray and ECHO everything was normal.Now I am under treatment for asthma.whats the reason for my hands shivering.