how to fix the unwanted auto selection in pen tool

Some pointers: 

• Try to use as few points as possible 

• If a curve has a vertical or horizontal tangent on can utilise that and set a Path Point there and fix the Bezier handles to run vertical or horizontal by pressing the shift-key when dragging them out

• If a curve flattens out into a straight part one should not create an unnecessary corner there but align the corresponding handle of a Curve Point with that straight stretch 

Bezier Handles determine the shape of the line connecting two path points, if you don’t want the point to have a forward handle you can eliminate it by alt-clicking the point before creating the next one. 

But quite frankly it seems you might need more provtice to fully understand how to make meaningful Paths and avoid nonsensical corners. 

Please post the image itself. 

Hi

It looks like you need  to learn to use the pen tool, in particular how to control the bezier handles to make curves and how to use the modifier keys to make sharp turns

See here:

https://helpx.adobe.com/photoshop/using/drawing-pen-tools.html

Dave