Here i got a method that can be used to detect click inside any polygon:

public bool PointInPolygon( Vector2 p, Vector2[] poly )
    {
        Vector2 p1, p2;
        bool inside = false;

        if( poly.Length < 3 )
        {
            return inside;
        }

        Vector2 oldPoint = new Vector2( poly[poly.Length - 1].X, poly[poly.Length - 1].Y );

        for( int i = 0; i < poly.Length; i++ )
        {
            Vector2 newPoint = new Vector2( poly[i].X, poly[i].Y );

            if( newPoint.X > oldPoint.X )
            {
                p1 = oldPoint;
                p2 = newPoint;
            }
            else
            {
                p1 = newPoint;
                p2 = oldPoint;
            }

            if( ( newPoint.X < p.X ) == ( p.X <= oldPoint.X )
                && ( (long)p.Y - (long)p1.Y ) * (long)( p2.X - p1.X )
                 < ( (long)p2.Y - (long)p1.Y ) * (long)( p.X - p1.X ) )
            {
                inside = !inside;
            }

            oldPoint = newPoint;
        }

        return inside;
    }

You need to give the corners in a vector2 array (poly) and the clicked position (p) to the method.

Here i got a method that can be used to detect clicks inside any polygon:

public bool PointInPolygon( Vector2 p, Vector2[] poly )
    {
        Vector2 p1, p2;
        bool inside = false;

        if( poly.Length < 3 )
        {
            return inside;
        }

        Vector2 oldPoint = new Vector2( poly[poly.Length - 1].X, poly[poly.Length - 1].Y );

        for( int i = 0; i < poly.Length; i++ )
        {
            Vector2 newPoint = new Vector2( poly[i].X, poly[i].Y );

            if( newPoint.X > oldPoint.X )
            {
                p1 = oldPoint;
                p2 = newPoint;
            }
            else
            {
                p1 = newPoint;
                p2 = oldPoint;
            }

            if( ( newPoint.X < p.X ) == ( p.X <= oldPoint.X )
                && ( (long)p.Y - (long)p1.Y ) * (long)( p2.X - p1.X )
                 < ( (long)p2.Y - (long)p1.Y ) * (long)( p.X - p1.X ) )
            {
                inside = !inside;
            }

            oldPoint = newPoint;
        }

        return inside;
    }

You need to give the corners of your hexagon in a vector2 array (poly) and the clicked position (p) to the method.