Finding distance between CLLocationCoordinate2D points

You should create an object of CLLocation using,

- (id)initWithLatitude:(CLLocationDegrees)latitude
    longitude:(CLLocationDegrees)longitude;

Then, you should be able to calculate the distance using

[location1 distanceFromLocation:location2];

If it is ok for you to get distance in meters between points, then

CLLocationCoordinate2D coordinate1 = <some value>
CLLocationCoordinate2D coordinate2 = <some value>
…
MKMapPoint point1 = MKMapPointForCoordinate(coordinate1);
MKMapPoint point2 = MKMapPointForCoordinate(coordinate2);
CLLocationDistance distance = MKMetersBetweenMapPoints(point1, point2);

will return the distance between two points. No needs to create CLLocation by given CLLocationCoordinate2D. This defines are available since iOS 4.0

Swift 5:

extension CLLocation {
    
    /// Get distance between two points
    ///
    /// - Parameters:
    ///   - from: first point
    ///   - to: second point
    /// - Returns: the distance in meters
    class func distance(from: CLLocationCoordinate2D, to: CLLocationCoordinate2D) -> CLLocationDistance {
        let from = CLLocation(latitude: from.latitude, longitude: from.longitude)
        let to = CLLocation(latitude: to.latitude, longitude: to.longitude)
        return from.distance(from: to)
    }
}