Cars should track straight. They drift to the right because of the road pitch. Roads are pitched so that rainwater flows off the side of the road.

As far as why it pulls, it's probably an alignment issue. Could be caused from damaged or worn suspension components. An alignment shop will correct any errors by either adjusting or replacing parts.

Could just be a flat or under inflated tyre.

A wheel balancing and a front end alignment. Typically cars are meant to 'drift to the right'. Reason for this is if you fall asleep behind the wheel, the car will drift towards the right. Preventing a head on collision. A 'Pull' is serious. Do not hesitate to get it checked.

You need a front end alignment