What is it called when someone is born with an almost unusable left side? Can't fully open left hand, finger are mulfuntioning, I walk with a limp, left shoulder twitches.

Hemiplegia. You could have been born with mild CP causing hemiplegia or spasticity on one half of the body.
There. There are many conditions that can result in the type of neurological conditions you described in your post (at birth). It is difficult to say exactly what you suffer from without having more information. The most common conditions are cerebral hemorrhage, stroke, infections, trauma, and cerebral palsy. Your doctor will be able to help you uncover the diagnosis with a more detailed history. Also ask your mother/family members, and even obtain medical records from your birth. Good luck.