Lately my right hand always felt numb from shoulder to finger. Why its happen? What to do?

Numb arm and hand. See your family doctor or a neurologist. The causes can be early stroke, compression of the nerves or blood vessels at the base of the neck from tumors or abscesses or muscle spasm in the scalene muscles. A careful and accurate history, neurologic examination, sometimes a scan are required before determining treatment. If it is early stroke, it requires emergent attention.
Need evaluation. It could be anything including just sleeping funney, butit also has potential to be more serious including multiple sclerosis carpal tunnel cervial disc disease on any way you need to be seen for an evaluation.