@llc777 It sounds like you have muscle spasms and neck tightness right up to your jaw. I have thoracic outlet syndrome which does cause tightness to the jaw, scapula area and between the collar bone and rib cage. My PT has treated this with myofascial release which loosens tight fascia. Scar tissue also creates tightness, and likely that is happening to you at 4 months post op. You may want to read this discussion on MFR. I have done a lot of it and it helps me. If you release the extra pressure, it may relieve pain. You'll need clearance from your surgeon. There is a provider search at https://mfrtherapists.com/

Neuropathy - "Myofascial Release Therapy (MFR) for treating compression and pain"
https://connect.mayoclinic.org/discussion/myofascial-release-therapy-mfr-for-treating-compression-and-pain/