One of our members co-authored a paper for PTs about ES, here’s a link, it might be helpful if you do find someone:
WESTBROOK et al. (2020) - Eagle’s syndrome, elongated styloid process and new evidence for pre-manipulative precautions for potential cervical arterial dysfunction – Doctor info and research article - General / Research Papers - Living with Eagle
It doesn’t help that we’re all different and what might help one is a big no-no for others! I did very gentle chin tucks laying down which helped the muscles at the back of my neck, but others have been told definitely not to do this if you had IJV compression! And I had traction & manipulation done when I had my whiplash injury 25 years ago- it was supposedly the best treatment at the time, but it was agony for me & made it so much worse! I just thought I’d throw that in there as @JugularEagle mentioned traction helped her!
Poor you with costochondritis too 
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