Great to hear you are seeing some improvements in your situation and are addressing your posture as you implement mobility work.
Have you used a supernivito (smaller supernova) in place of a lacrosse ball?
When you are working on things are you able to breathe the whole time?
If you are not able to breathe you are going too deep.

Working up and down stream of the trap?
As things start to resolve there may be a step back before a step ahead.
You are unlearning one habit/position and establishing a new habit/position.
A few to check out
Saturday, December 17, 2016- Neck
Monday January 23rd, 2017- Neck
Episode 130 One Million Episodes Viewed!
 Pro Episode #18 Pro User Request Friday The Upper Trap Tweak
Saturday March 11.2017 Neck & Traps
Friday May 19, 2017 Trap Scrub