Struggling with mechanics

I’m going to be a junior now, and I’m playing summer ball. But I’m really struggling with my mechanics, and I have yet to find any real consistency.
So here’s my problems:

  • Dragging back foot. (I’m a right-hander) Like I’m dragging my foot to the point where I get cuts on the inside part of my back foot. It’s pretty bad.
    -When I release my fastball, it is usually high or low, or off to the left where I am facing. Sometimes low to the point it bounces before the plate.
    -I do a over the top delivery, but again my pitches go up, down, and left.
    -I tend to stand up straight a lot after finishing my pitch.
    -My offspeed pitches go off to the way low left or they are high. I through a change up, and a fastball.
    Here’s what my coaches say:
    “Bend your back.” Yeah I know to do that, but is there any like way to make myself bend my back over after I follow through?
    “Longer Stride” Does that even help me bend my back?
    And last thing is, I know I have to throw my hips in when I pitch, but when is the proper time to explode and twist my hips when pitching?
    I do not go out of the wind up, I go out of the stretch with medium compacted leg kick, and with no leg kick at all.
    If you guys can help me out with all this, thatd be really really great.

why don’t you post video?

that will be a lot easier for many people here to provide advice with their expertise or experience