Correct me if I'm wrong but pinch collar is prong collar yes? I've had my share of collars with my pup (going on 12 months). At 8 weeks he had a regular collar, which was ok until he'd gotten bigger and started pulling.
And then I had the harness (always on the front clip. Use back clip only for pulling eg. When you're rollerblading/skating and he's supposed to pull you), which of course worked since he is UNABLE to pull when he has it on the front clip. But him being unable to pull doesn't mean he won't, so the front clip harness is NOT training, just a tool to MAKE him not pull, instead of TEACHING.
So I did some research and landed on choke collar. Worked quite wonderfully during 'no pull' training. Put it all the way up in the neck behind the ears (Cesar Millan style), and he will understand that if he pulls, he chokes. That's what I have him on now, almost at all times. Still use the harness sometimes when we're hiking or at the beach, hiking sometimes I want him to pull me as we go uphill (hahhha) and at the beach / crowded public places like malls and stuff, just as a precaution if anything happens I can pull him with the handle on the harness.
I experimented on Prong collar too. Nope. Doesn't work (I've had a trainer showed me how to do it properly). Still doesn't work. He just pulls and pulls and pulls and doesn't even stop him from jumping. So no prongs for me. I know some people like using it and it DOES work for a lot of dogs and owners. Just not me and my boy. Plus personally it just looks uncomfortable so I opted it out.
Try the choke collar, honestly.
And also, just a suggestion, when we had one of our sessions with the trainer and my boy pulls, I kept saying 'No pull! No pull!' out trainer corrected me and said, 'Don't tell him what NOT TO DO. Tell him WHAT TO DO. Like, Heel! Instead of No pull!' Makes a lot of sense to me. Not only does he NOT pull, he now HEELS.
Here's a picture of my boy with his choke collar. (size 22", boy's neck is 19" at the moment). He's wearing a tutu. Ignore it. It's the only photo I can find right now lol.
Give it a go.